- add BR2_PREFER_STATIC_LIB config option to be able to select if we prefer to build static or dynamic libs/bins.

- depending on the BR2_GNU_BUILD_SUFFIX, set the respective EXEEXT, LIBEXT, SHREXT extensions for use on the target.
Thanks to Tom for suplying a diff which implements these.

Config.in

@@ -373,6 +373,19 @@ config BR2_DEPRECATED
 	help
 	  This option hides outdated/obsolete versions of packages.
 
+config BR2_PREFER_STATIC_LIB
+	bool "prefer static libraries"
+	default n
+	help
+	  Where possible, use static libraries.
+	  This increases your code size a lot and should only be
+	  used with a good reason why not use the default, which
+	  is dynamic libraries.
+
+	  If unsure, say No.
+
+	  WARNING: This is highly experimental at the moment.
+
 endmenu
 
 source "toolchain/Config.in"

Makefile

@@ -66,7 +66,32 @@ include package/Makefile.in
 #
 #############################################################
 
+ifneq (,$(findstring linux,$(BR2_GNU_BUILD_SUFFIX)))
+EXEEXT:=
+LIBEXT:=.a
+SHREXT:=.so
+endif
+ifneq (,$(findstring apple,$(BR2_GNU_BUILD_SUFFIX)))
+EXEEXT:=.pear
+LIBEXT:=.dunno
+SHREXT:=.dylib
+endif
+ifneq (,$(findstring cygwin,$(BR2_GNU_BUILD_SUFFIX)))
+EXEEXT:=.exe
+LIBEXT:=.lib
+SHREXT:=.dll
+endif
+ifneq (,$(findstring mingw,$(BR2_GNU_BUILD_SUFFIX)))
+EXEEXT:=.exe
+LIBEXT:=.lib
+SHREXT:=.dll
+endif
 
+ifeq ($(BR2_PREFER_STATIC_LIB),y)
+LIBTGTEXT=$(LIBEXT)
+else
+LIBTGTEXT=$(SHREXT)
+endif
 
 all:   world
 

package/gmp/gmp.mk

@@ -18,6 +18,14 @@ else
 GMP_BE:=no
 endif
 
+# this is a workaround for a bug in GMP, please see 
+# http://gmplib.org/list-archives/gmp-devel/2006-April/000618.html
+ifeq ($(EXEEXT),.exe)
+GMP_CPP_FLAGS:=-DDLL_EXPORT
+else
+GMP_CPP_FLAGS:=
+endif
+
 $(DL_DIR)/$(GMP_SOURCE):
 	 $(WGET) -P $(DL_DIR) $(GMP_SITE)/$(GMP_SOURCE)
 
@@ -35,6 +43,7 @@ $(GMP_TARGET_DIR)/.configured: $(GMP_DIR)/.unpacked
 		$(TARGET_CONFIGURE_OPTS) \
 		CFLAGS="$(TARGET_CFLAGS)" \
 		LDFLAGS="$(TARGET_LDFLAGS)" \
+		CPPFLAGS="$(GMP_CPP_FLAGS)" \
 		ac_cv_c_bigendian=$(GMP_BE) \
 		$(GMP_DIR)/configure \
 		--target=$(GNU_TARGET_NAME) \
@@ -52,7 +61,7 @@ $(GMP_TARGET_DIR)/.configured: $(GMP_DIR)/.unpacked
 		--includedir=/include \
 		--mandir=/usr/man \
 		--infodir=/usr/info \
-		--enable-shared \
+		$(PREFERRED_LIB_FLAGS) \
 		$(DISABLE_NLS) \
 	);
 	touch $@
@@ -105,12 +114,12 @@ $(GMP_DIR2)/.configured: $(GMP_DIR)/.unpacked
 		CC_FOR_BUILD="$(HOSTCC)" \
 		CC="$(HOSTCC)" \
 		CFLAGS="$(HOST_CFLAGS)" \
+		CPPFLAGS="$(GMP_CPP_FLAGS)" \
 		$(GMP_DIR)/configure \
 		--prefix="$(GMP_HOST_DIR)" \
 		--build=$(GNU_HOST_NAME) \
 		--host=$(GNU_HOST_NAME) \
-		--enable-shared \
-		--enable-static \
+		$(PREFERRED_LIB_FLAGS) \
 		$(DISABLE_NLS) \
 	);
 	touch $@

toolchain/Makefile.in

@@ -10,6 +10,12 @@ else
 MULTILIB:=--disable-multilib
 endif
 
+ifeq ($(BR2_PREFER_STATIC_LIB),y)
+PREFERRED_LIB_FLAGS:=--enable-static --disable-shared
+else
+PREFERRED_LIB_FLAGS:=--disable-static --enable-shared
+endif
+
 
 # FIXME -- this is temporary
 OPTIMIZE_FOR_CPU=$(ARCH)