Introduce CMake support for configuring Git

At the moment, the recommended way to configure Git's builds is to
simply run `make`. If that does not work, the recommended strategy is to
look at the top of the `Makefile` to see whether any "Makefile knob" has
to be turned on/off, e.g. `make NO_OPENSSL=YesPlease`.

Alternatively, Git also has an `autoconf` setup which allows configuring
builds via `./configure [<option>...]`.

Both of these options are fine if the developer works on Unix or Linux.
But on Windows, we have to jump through hoops to configure a build
(read: we force the user to install a full Git for Windows SDK, which
occupies around two gigabytes (!) on disk and downloads about three
quarters of a gigabyte worth of Git objects).

The build infrastructure for Git is written around being able to run
make, which is not supported natively on Windows.
To help Windows developers a CMake build script is introduced here.

With a working support CMake, developers on Windows need only install
CMake, configure their build, load the generated Visual Studio solution
and immediately start modifying the code and build their own version of
Git. Likewise, developers on other platforms can use the convenient GUI
tools provided by CMake to configure their build.

So let's start building CMake support for Git.

This is only the first step, and to make it easier to review, it only
allows for configuring builds on the platform that is easiest to
configure for: Linux.

The CMake script checks whether the headers are present(eg. libgen.h),
whether the functions are present(eg. memmem), whether the funtions work
properly (eg. snprintf) and generate the required compile definitions
for the platform. The script also searches for the required libraries,
if it fails to find the required libraries the respective executables
won't be built.(eg. If libcurl is not found then git-remote-http won't
be built). This will help building Git easier.

With a CMake script an out of source build of git is possible resulting
in a clean source tree.

Note: this patch asks for the minimum version v3.14 of CMake (which is
not all that old as of time of writing) because that is the first
version to offer a platform-independent way to generate hardlinks as
part of the build. This is needed to generate all those hardlinks for
the built-in commands of Git.

Signed-off-by: Sibi Siddharthan <sibisiddharthan.github@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Sibi Siddharthan 2020-06-12 18:29:19 +00:00 committed by Junio C Hamano
parent 0313f36c6e
commit 061c2240b1

View File

@ -0,0 +1,592 @@
#
# Copyright (c) 2020 Sibi Siddharthan
#
#[[
Instructions to run CMake:
cmake `relative-path-to-CMakeLists.txt` -DCMAKE_BUILD_TYPE=Release
Eg.
From the root of git source tree
`cmake contrib/buildsystems/ `
This will build the git binaries at the root
For out of source builds, say build in 'git/git-build/'
`mkdir git-build;cd git-build; cmake ../contrib/buildsystems/`
This will build the git binaries in git-build directory
Possible build configurations(-DCMAKE_BUILD_TYPE) with corresponding
compiler flags
Debug : -g
Release: -O3
RelWithDebInfo : -O2 -g
MinSizeRel : -Os
empty(default) :
NOTE: -DCMAKE_BUILD_TYPE is optional. For multi-config generators like Visual Studio
this option is ignored
This process generates a Makefile(Linux/*BSD/MacOS) , Visual Studio solution(Windows) by default.
Run `make` to build Git on Linux/*BSD/MacOS.
Open git.sln on Windows and build Git.
NOTE: By default CMake uses Makefile as the build tool on Linux and Visual Studio in Windows,
to use another tool say `ninja` add this to the command line when configuring.
`-G Ninja`
]]
cmake_minimum_required(VERSION 3.14)
#set the source directory to root of git
set(CMAKE_SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/../..)
find_program(SH_EXE sh)
#Create GIT-VERSION-FILE using GIT-VERSION-GEN
if(NOT EXISTS ${CMAKE_SOURCE_DIR}/GIT-VERSION-FILE)
message("Generating GIT-VERSION-FILE")
execute_process(COMMAND ${SH_EXE} ${CMAKE_SOURCE_DIR}/GIT-VERSION-GEN
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR})
endif()
#Parse GIT-VERSION-FILE to get the version
file(STRINGS ${CMAKE_SOURCE_DIR}/GIT-VERSION-FILE git_version REGEX "GIT_VERSION = (.*)")
string(REPLACE "GIT_VERSION = " "" git_version ${git_version})
string(FIND ${git_version} "GIT" location)
if(location EQUAL -1)
string(REGEX MATCH "[0-9]*\\.[0-9]*\\.[0-9]*" git_version ${git_version})
else()
string(REGEX MATCH "[0-9]*\\.[0-9]*" git_version ${git_version})
string(APPEND git_version ".0") #for building from a snapshot
endif()
project(git
VERSION ${git_version}
LANGUAGES C)
#macros for parsing the Makefile for sources
macro(parse_makefile_for_sources list_var regex)
file(STRINGS ${CMAKE_SOURCE_DIR}/Makefile ${list_var} REGEX "^${regex} \\+=(.*)")
string(REPLACE "${regex} +=" "" ${list_var} ${${list_var}})
string(REPLACE "$(COMPAT_OBJS)" "" ${list_var} ${${list_var}}) #remove "$(COMPAT_OBJS)" This is only for libgit.
string(STRIP ${${list_var}} ${list_var}) #remove trailing/leading whitespaces
string(REPLACE ".o" ".c;" ${list_var} ${${list_var}}) #change .o to .c, ; is for converting the string into a list
list(TRANSFORM ${list_var} STRIP) #remove trailing/leading whitespaces for each element in list
list(REMOVE_ITEM ${list_var} "") #remove empty list elements
endmacro()
include(CheckTypeSize)
include(CheckCSourceRuns)
include(CheckCSourceCompiles)
include(CheckIncludeFile)
include(CheckFunctionExists)
include(CheckSymbolExists)
include(CheckStructHasMember)
find_package(ZLIB REQUIRED)
find_package(CURL)
find_package(EXPAT)
find_package(Iconv)
find_package(Intl)
if(NOT Intl_FOUND)
add_compile_definitions(NO_GETTEXT)
if(NOT Iconv_FOUND)
add_compile_definitions(NO_ICONV)
endif()
endif()
include_directories(SYSTEM ${ZLIB_INCLUDE_DIRS})
if(CURL_FOUND)
include_directories(SYSTEM ${CURL_INCLUDE_DIRS})
endif()
if(EXPAT_FOUND)
include_directories(SYSTEM ${EXPAT_INCLUDE_DIRS})
endif()
if(Iconv_FOUND)
include_directories(SYSTEM ${Iconv_INCLUDE_DIRS})
endif()
if(Intl_FOUND)
include_directories(SYSTEM ${Intl_INCLUDE_DIRS})
endif()
#default behaviour
include_directories(${CMAKE_SOURCE_DIR})
add_compile_definitions(GIT_HOST_CPU="${CMAKE_SYSTEM_PROCESSOR}")
add_compile_definitions(SHA256_BLK INTERNAL_QSORT RUNTIME_PREFIX)
add_compile_definitions(NO_OPENSSL SHA1_DC SHA1DC_NO_STANDARD_INCLUDES
SHA1DC_INIT_SAFE_HASH_DEFAULT=0
SHA1DC_CUSTOM_INCLUDE_SHA1_C="cache.h"
SHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C="git-compat-util.h" )
list(APPEND compat_SOURCES sha1dc_git.c sha1dc/sha1.c sha1dc/ubc_check.c block-sha1/sha1.c sha256/block/sha256.c compat/qsort_s.c)
add_compile_definitions(PAGER_ENV="LESS=FRX LV=-c"
ETC_GITATTRIBUTES="etc/gitattributes"
ETC_GITCONFIG="etc/gitconfig"
GIT_EXEC_PATH="libexec/git-core"
GIT_LOCALE_PATH="share/locale"
GIT_MAN_PATH="share/man"
GIT_INFO_PATH="share/info"
GIT_HTML_PATH="share/doc/git-doc"
DEFAULT_HELP_FORMAT="html"
DEFAULT_GIT_TEMPLATE_DIR="share/git-core/templates"
GIT_VERSION="${PROJECT_VERSION}.GIT"
GIT_USER_AGENT="git/${PROJECT_VERSION}.GIT"
BINDIR="bin"
GIT_BUILT_FROM_COMMIT="")
set(FALLBACK_RUNTIME_PREFIX /home/$ENV{USER})
add_compile_definitions(FALLBACK_RUNTIME_PREFIX="${FALLBACK_RUNTIME_PREFIX}")
add_compile_definitions(PROCFS_EXECUTABLE_PATH="/proc/self/exe" HAVE_DEV_TTY )
list(APPEND compat_SOURCES unix-socket.c)
#header checks
check_include_file(libgen.h HAVE_LIBGEN_H)
if(NOT HAVE_LIBGEN_H)
add_compile_definitions(NO_LIBGEN_H)
list(APPEND compat_SOURCES compat/basename.c)
endif()
check_include_file(sys/sysinfo.h HAVE_SYSINFO)
if(HAVE_SYSINFO)
add_compile_definitions(HAVE_SYSINFO)
endif()
check_c_source_compiles("
#include <alloca.h>
int main(void)
{
char *p = (char *) alloca(2 * sizeof(int));
if (p)
return 0;
return 0;
}"
HAVE_ALLOCA_H)
if(HAVE_ALLOCA_H)
add_compile_definitions(HAVE_ALLOCA_H)
endif()
check_include_file(strings.h HAVE_STRINGS_H)
if(HAVE_STRINGS_H)
add_compile_definitions(HAVE_STRINGS_H)
endif()
check_include_file(sys/select.h HAVE_SYS_SELECT_H)
if(NOT HAVE_SYS_SELECT_H)
add_compile_definitions(NO_SYS_SELECT_H)
endif()
check_include_file(sys/poll.h HAVE_SYS_POLL_H)
if(NOT HAVE_SYS_POLL_H)
add_compile_definitions(NO_SYS_POLL_H)
endif()
check_include_file(poll.h HAVE_POLL_H)
if(NOT HAVE_POLL_H)
add_compile_definitions(NO_POLL_H)
endif()
check_include_file(inttypes.h HAVE_INTTYPES_H)
if(NOT HAVE_INTTYPES_H)
add_compile_definitions(NO_INTTYPES_H)
endif()
check_include_file(paths.h HAVE_PATHS_H)
if(HAVE_PATHS_H)
add_compile_definitions(HAVE_PATHS_H)
endif()
#function checks
set(function_checks
strcasestr memmem strlcpy strtoimax strtoumax strtoull
setenv mkdtemp poll pread memmem unsetenv hstrerror)
foreach(f ${function_checks})
string(TOUPPER ${f} uf)
check_function_exists(${f} HAVE_${uf})
if(NOT HAVE_${uf})
add_compile_definitions(NO_${uf})
endif()
endforeach()
if(NOT HAVE_POLL_H OR NOT HAVE_SYS_POLL_H OR NOT HAVE_POLL)
include_directories(${CMAKE_SOURCE_DIR}/compat/poll)
add_compile_definitions(NO_POLL)
list(APPEND compat_SOURCES compat/poll/poll.c)
endif()
if(NOT HAVE_STRCASESTR)
list(APPEND compat_SOURCES compat/strcasestr.c)
endif()
if(NOT HAVE_STRLCPY)
list(APPEND compat_SOURCES compat/strlcpy.c)
endif()
if(NOT HAVE_STRTOUMAX)
list(APPEND compat_SOURCES compat/strtoumax.c compat/strtoimax.c)
endif()
if(NOT HAVE_SETENV)
list(APPEND compat_SOURCES compat/setenv.c)
endif()
if(NOT HAVE_MKDTEMP)
list(APPEND compat_SOURCES compat/mkdtemp.c)
endif()
if(NOT HAVE_PREAD)
list(APPEND compat_SOURCES compat/pread.c)
endif()
if(NOT HAVE_MEMMEM)
list(APPEND compat_SOURCES compat/memmem.c)
endif()
if(NOT WIN32)
if(NOT HAVE_UNSETENV)
list(APPEND compat_SOURCES compat/unsetenv.c)
endif()
if(NOT HAVE_HSTRERROR)
list(APPEND compat_SOURCES compat/hstrerror.c)
endif()
endif()
check_function_exists(getdelim HAVE_GETDELIM)
if(HAVE_GETDELIM)
add_compile_definitions(HAVE_GETDELIM)
endif()
check_function_exists(clock_gettime HAVE_CLOCK_GETTIME)
check_symbol_exists(CLOCK_MONOTONIC "time.h" HAVE_CLOCK_MONOTONIC)
if(HAVE_CLOCK_GETTIME)
add_compile_definitions(HAVE_CLOCK_GETTIME)
endif()
if(HAVE_CLOCK_MONOTONIC)
add_compile_definitions(HAVE_CLOCK_MONOTONIC)
endif()
#check for st_blocks in struct stat
check_struct_has_member("struct stat" st_blocks "sys/stat.h" STRUCT_STAT_HAS_ST_BLOCKS)
if(NOT STRUCT_STAT_HAS_ST_BLOCKS)
add_compile_definitions(NO_ST_BLOCKS_IN_STRUCT_STAT)
endif()
#compile checks
check_c_source_runs("
#include<stdio.h>
#include<stdarg.h>
#include<string.h>
#include<stdlib.h>
int test_vsnprintf(char *str, size_t maxsize, const char *format, ...)
{
int ret;
va_list ap;
va_start(ap, format);
ret = vsnprintf(str, maxsize, format, ap);
va_end(ap);
return ret;
}
int main(void)
{
char buf[6];
if (test_vsnprintf(buf, 3, \"%s\", \"12345\") != 5
|| strcmp(buf, \"12\"))
return 1;
if (snprintf(buf, 3, \"%s\", \"12345\") != 5
|| strcmp(buf, \"12\"))
return 1;
return 0;
}"
SNPRINTF_OK)
if(NOT SNPRINTF_OK)
add_compile_definitions(SNPRINTF_RETURNS_BOGUS)
list(APPEND compat_SOURCES compat/snprintf.c)
endif()
check_c_source_runs("
#include<stdio.h>
int main(void)
{
FILE *f = fopen(\".\", \"r\");
return f != NULL;
}"
FREAD_READS_DIRECTORIES_NO)
if(NOT FREAD_READS_DIRECTORIES_NO)
add_compile_definitions(FREAD_READS_DIRECTORIES)
list(APPEND compat_SOURCES compat/fopen.c)
endif()
check_c_source_compiles("
#include <regex.h>
#ifndef REG_STARTEND
#error oops we dont have it
#endif
int main(void)
{
return 0;
}"
HAVE_REGEX)
if(NOT HAVE_REGEX)
include_directories(${CMAKE_SOURCE_DIR}/compat/regex)
list(APPEND compat_SOURCES compat/regex/regex.c )
add_compile_definitions(NO_REGEX NO_MBSUPPORT GAWK)
endif()
check_c_source_compiles("
#include <stddef.h>
#include <sys/types.h>
#include <sys/sysctl.h>
int main(void)
{
int val, mib[2];
size_t len;
mib[0] = CTL_HW;
mib[1] = 1;
len = sizeof(val);
return sysctl(mib, 2, &val, &len, NULL, 0) ? 1 : 0;
}"
HAVE_BSD_SYSCTL)
if(HAVE_BSD_SYSCTL)
add_compile_definitions(HAVE_BSD_SYSCTL)
endif()
set(CMAKE_REQUIRED_LIBRARIES ${Iconv_LIBRARIES})
set(CMAKE_REQUIRED_INCLUDES ${Iconv_INCLUDE_DIRS})
check_c_source_compiles("
#include <iconv.h>
extern size_t iconv(iconv_t cd,
char **inbuf, size_t *inbytesleft,
char **outbuf, size_t *outbytesleft);
int main(void)
{
return 0;
}"
HAVE_NEW_ICONV)
if(HAVE_NEW_ICONV)
set(HAVE_OLD_ICONV 0)
else()
set(HAVE_OLD_ICONV 1)
endif()
check_c_source_runs("
#include <iconv.h>
#if ${HAVE_OLD_ICONV}
typedef const char *iconv_ibp;
#else
typedef char *iconv_ibp;
#endif
int main(void)
{
int v;
iconv_t conv;
char in[] = \"a\";
iconv_ibp pin = in;
char out[20] = \"\";
char *pout = out;
size_t isz = sizeof(in);
size_t osz = sizeof(out);
conv = iconv_open(\"UTF-16\", \"UTF-8\");
iconv(conv, &pin, &isz, &pout, &osz);
iconv_close(conv);
v = (unsigned char)(out[0]) + (unsigned char)(out[1]);
return v != 0xfe + 0xff;
}"
ICONV_DOESNOT_OMIT_BOM)
if(NOT ICONV_DOESNOT_OMIT_BOM)
add_compile_definitions(ICONV_OMITS_BOM)
endif()
unset(CMAKE_REQUIRED_LIBRARIES)
unset(CMAKE_REQUIRED_INCLUDES)
#programs
set(PROGRAMS_BUILT
git git-bugreport git-credential-store git-daemon git-fast-import git-http-backend git-sh-i18n--envsubst
git-shell git-remote-testsvn git-credential-cache git-credential-cache--daemon)
if(NOT CURL_FOUND)
list(APPEND excluded_progs git-http-fetch git-http-push)
add_compile_definitions(NO_CURL)
message(WARNING "git-http-push and git-http-fetch will not be built")
else()
list(APPEND PROGRAMS_BUILT git-http-fetch git-http-push git-imap-send git-remote-http)
if(CURL_VERSION_STRING VERSION_GREATER_EQUAL 7.34.0)
add_compile_definitions(USE_CURL_FOR_IMAP_SEND)
endif()
endif()
if(NOT EXPAT_FOUND)
list(APPEND excluded_progs git-http-push)
add_compile_definitions(NO_EXPAT)
else()
list(APPEND PROGRAMS_BUILT git-http-push)
if(EXPAT_VERSION_STRING VERSION_LESS_EQUAL 1.2)
add_compile_definitions(EXPAT_NEEDS_XMLPARSE_H)
endif()
endif()
list(REMOVE_DUPLICATES excluded_progs)
list(REMOVE_DUPLICATES PROGRAMS_BUILT)
foreach(p ${excluded_progs})
list(APPEND EXCLUSION_PROGS --exclude-program ${p} )
endforeach()
#for comparing null values
list(APPEND EXCLUSION_PROGS empty)
set(EXCLUSION_PROGS_CACHE ${EXCLUSION_PROGS} CACHE STRING "Programs not built" FORCE)
if(NOT EXISTS ${CMAKE_BINARY_DIR}/command-list.h OR NOT EXCLUSION_PROGS_CACHE STREQUAL EXCLUSION_PROGS)
list(REMOVE_ITEM EXCLUSION_PROGS empty)
message("Generating command-list.h")
execute_process(COMMAND ${SH_EXE} ${CMAKE_SOURCE_DIR}/generate-cmdlist.sh ${EXCLUSION_PROGS} command-list.txt
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
OUTPUT_FILE ${CMAKE_BINARY_DIR}/command-list.h)
endif()
if(NOT EXISTS ${CMAKE_BINARY_DIR}/config-list.h)
message("Generating config-list.h")
execute_process(COMMAND ${SH_EXE} ${CMAKE_SOURCE_DIR}/generate-configlist.sh
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
OUTPUT_FILE ${CMAKE_BINARY_DIR}/config-list.h)
endif()
include_directories(${CMAKE_BINARY_DIR})
#build
#libgit
parse_makefile_for_sources(libgit_SOURCES "LIB_OBJS")
list(TRANSFORM libgit_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
list(TRANSFORM compat_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
add_library(libgit ${libgit_SOURCES} ${compat_SOURCES})
#libxdiff
parse_makefile_for_sources(libxdiff_SOURCES "XDIFF_OBJS")
list(TRANSFORM libxdiff_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
add_library(xdiff STATIC ${libxdiff_SOURCES})
#libvcs-svn
parse_makefile_for_sources(libvcs-svn_SOURCES "VCSSVN_OBJS")
list(TRANSFORM libvcs-svn_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
add_library(vcs-svn STATIC ${libvcs-svn_SOURCES})
#link all required libraries to common-main
add_library(common-main OBJECT ${CMAKE_SOURCE_DIR}/common-main.c)
target_link_libraries(common-main libgit xdiff ${ZLIB_LIBRARIES} pthread rt)
if(Intl_FOUND)
target_link_libraries(common-main ${Intl_LIBRARIES})
endif()
if(Iconv_FOUND)
target_link_libraries(common-main ${Iconv_LIBRARIES})
endif()
#git
parse_makefile_for_sources(git_SOURCES "BUILTIN_OBJS")
list(TRANSFORM git_SOURCES PREPEND "${CMAKE_SOURCE_DIR}/")
add_executable(git ${CMAKE_SOURCE_DIR}/git.c ${git_SOURCES})
target_link_libraries(git common-main)
add_executable(git-bugreport ${CMAKE_SOURCE_DIR}/bugreport.c)
target_link_libraries(git-bugreport common-main)
add_executable(git-credential-store ${CMAKE_SOURCE_DIR}/credential-store.c)
target_link_libraries(git-credential-store common-main)
add_executable(git-daemon ${CMAKE_SOURCE_DIR}/daemon.c)
target_link_libraries(git-daemon common-main)
add_executable(git-fast-import ${CMAKE_SOURCE_DIR}/fast-import.c)
target_link_libraries(git-fast-import common-main)
add_executable(git-http-backend ${CMAKE_SOURCE_DIR}/http-backend.c)
target_link_libraries(git-http-backend common-main)
add_executable(git-sh-i18n--envsubst ${CMAKE_SOURCE_DIR}/sh-i18n--envsubst.c)
target_link_libraries(git-sh-i18n--envsubst common-main)
add_executable(git-shell ${CMAKE_SOURCE_DIR}/shell.c)
target_link_libraries(git-shell common-main)
if(CURL_FOUND)
add_library(http_obj OBJECT ${CMAKE_SOURCE_DIR}/http.c)
add_executable(git-imap-send ${CMAKE_SOURCE_DIR}/imap-send.c)
target_link_libraries(git-imap-send http_obj common-main ${CURL_LIBRARIES})
add_executable(git-http-fetch ${CMAKE_SOURCE_DIR}/http-walker.c ${CMAKE_SOURCE_DIR}/http-fetch.c)
target_link_libraries(git-http-fetch http_obj common-main ${CURL_LIBRARIES})
add_executable(git-remote-http ${CMAKE_SOURCE_DIR}/http-walker.c ${CMAKE_SOURCE_DIR}/remote-curl.c)
target_link_libraries(git-remote-http http_obj common-main ${CURL_LIBRARIES} )
if(EXPAT_FOUND)
add_executable(git-http-push ${CMAKE_SOURCE_DIR}/http-push.c)
target_link_libraries(git-http-push http_obj common-main ${CURL_LIBRARIES} ${EXPAT_LIBRARIES})
endif()
endif()
add_executable(git-remote-testsvn ${CMAKE_SOURCE_DIR}/remote-testsvn.c)
target_link_libraries(git-remote-testsvn common-main vcs-svn)
add_executable(git-credential-cache ${CMAKE_SOURCE_DIR}/credential-cache.c)
target_link_libraries(git-credential-cache common-main)
add_executable(git-credential-cache--daemon ${CMAKE_SOURCE_DIR}/credential-cache--daemon.c)
target_link_libraries(git-credential-cache--daemon common-main)
set(git_builtin_extra
cherry cherry-pick format-patch fsck-objects
init merge-subtree restore show
stage status switch whatchanged)
#Creating hardlinks
foreach(s ${git_SOURCES} ${git_builtin_extra})
string(REPLACE "${CMAKE_SOURCE_DIR}/builtin/" "" s ${s})
string(REPLACE ".c" "" s ${s})
file(APPEND ${CMAKE_BINARY_DIR}/CreateLinks.cmake "file(CREATE_LINK git git-${s})\n")
list(APPEND git_links ${CMAKE_BINARY_DIR}/git-${s})
endforeach()
if(CURL_FOUND)
set(remote_exes
git-remote-https git-remote-ftp git-remote-ftps)
foreach(s ${remote_exes})
file(APPEND ${CMAKE_BINARY_DIR}/CreateLinks.cmake "file(CREATE_LINK git-remote-http ${s})\n")
list(APPEND git_http_links ${CMAKE_BINARY_DIR}/${s})
endforeach()
endif()
add_custom_command(OUTPUT ${git_links} ${git_http_links}
COMMAND ${CMAKE_COMMAND} -P ${CMAKE_BINARY_DIR}/CreateLinks.cmake
DEPENDS git git-remote-http)
add_custom_target(git-links ALL DEPENDS ${git_links} ${git_http_links})