Update PKGBUILD to be more inline with community/ncnn

.SRCINFO

@@ -1,6 +1,6 @@
 pkgbase = ncnn-git
 	pkgdesc = High-performance neural network inference framework optimized for the mobile platform
-	pkgver = 20220216.r57.g3d169b323
+	pkgver = 20220721.r2.g13a953398
 	pkgrel = 1
 	url = https://github.com/Tencent/ncnn
 	arch = i686
@@ -12,6 +12,7 @@ pkgbase = ncnn-git
 	makedepends = protobuf
 	makedepends = vulkan-headers
 	depends = glslang
+	optdepends = protobuf: for onnx2ncnn
 	provides = ncnn
 	conflicts = ncnn
 	source = git+https://github.com/Tencent/ncnn.git

PKGBUILD

@@ -4,13 +4,14 @@
 
 pkgname=ncnn-git
 _pkgname=ncnn
-pkgver=20220216.r57.g3d169b323
+pkgver=20220721.r2.g13a953398
 pkgrel=1
 pkgdesc="High-performance neural network inference framework optimized for the mobile platform"
 url="https://github.com/Tencent/ncnn"
 license=('BSD')
 depends=('glslang')
 makedepends=('git' 'cmake' 'vulkan-icd-loader' 'protobuf' 'vulkan-headers')
+optdepends=('protobuf: for onnx2ncnn')
 conflicts=('ncnn')
 provides=('ncnn')
 arch=('i686' 'x86_64')
@@ -39,14 +40,22 @@ prepare() {
 
 build() {
     cd "${srcdir}/ncnn"
-    mkdir -p build
-    cd build
+    if [[ ! -d build ]]
+    then
+        mkdir build && cd build
+    else
+        cd build
+    fi
     cmake \
         -DCMAKE_INSTALL_PREFIX=/usr \
+        -DCMAKE_BUILD_TYPE='None' \
         -DNCNN_BUILD_EXAMPLES=OFF \
         -DNCNN_VULKAN=ON \
         -DNCNN_SYSTEM_GLSLANG=ON \
+        -DNCNN_SHARED_LIB=ON \
+        -DNCNN_ENABLE_LTO=ON \
         -DGLSLANG_TARGET_DIR=/usr/lib/cmake \
+        -Wno-dev \
         ..
     make
 }