external/glm: work around missing clang-cl #pragma support

Change-Id: I596dc0e2306e7170e65c77a1635f88407272e6b1

external/glm/UnpackedTarball_glm.mk

@@ -19,6 +19,7 @@ $(eval $(call gb_UnpackedTarball_add_patches,glm, \
     external/glm/Wshadow-patch-fix.patch \
     external/glm/Wsign-compare.patch.0 \
     external/glm/Wunused-parameter.patch \
+    external/glm/clang-cl.patch.0 \
 ))
 
 # vim: set noet sw=4 ts=4:

external/glm/clang-cl.patch.0

+# "#pragma intrinsic" not (yet?) handled in the "if (LangOpts.MicrosoftExt)"
+# block in Preprocessor::RegisterBuiltinPragmas in Clang's lib/Lex/Pragma.cpp:
+--- glm/core/func_integer.inl
++++ glm/core/func_integer.inl
+@@ -29,7 +29,9 @@
+ #if(GLM_ARCH != GLM_ARCH_PURE)
+ #if(GLM_COMPILER & GLM_COMPILER_VC)
+ #	include <intrin.h>
++#if !defined __clang__
+ #	pragma intrinsic(_BitScanReverse)
++#endif
+ #endif//(GLM_COMPILER & GLM_COMPILER_VC)
+ #endif//(GLM_ARCH != GLM_ARCH_PURE)
+