From 32b2ea526649b5f02543c4bddec6069778ec0c54 Mon Sep 17 00:00:00 2001
From: Wes Tarro <dudamoos@users.noreply.github.com>
Date: Sat, 6 Feb 2016 13:10:02 -0500
Subject: [PATCH] Fixed building with GCC - needed different options and had to
 create a dummy DLL entry to avoid crashes.

---
 auto/src/glew_init_gl.c    |  4 +++-
 build/cmake/CMakeLists.txt | 15 +++++++++++----
 src/gcc_dll_entry.c        |  7 +++++++
 3 files changed, 21 insertions(+), 5 deletions(-)
 create mode 100644 src/gcc_dll_entry.c

diff --git a/auto/src/glew_init_gl.c b/auto/src/glew_init_gl.c
index 87503c3..7d783bf 100644
--- a/auto/src/glew_init_gl.c
+++ b/auto/src/glew_init_gl.c
@@ -124,7 +124,9 @@ static GLenum GLEWAPIENTRY glewContextInit ()
     GLEW_VERSION_1_1   = GLEW_VERSION_1_2   == GL_TRUE || ( major == 1 && minor >= 1 ) ? GL_TRUE : GL_FALSE;
   }
 
-  for (size_t i = 0; i < sizeof(_glewExtensionLookup) / sizeof(char*); ++i) _glewExtensionString[i] = GL_FALSE;
+  size_t n;
+  for (n = 0; n < sizeof(_glewExtensionString) / sizeof(_glewExtensionString[0]); ++n)
+    _glewExtensionString[n] = GL_FALSE;
 
   if (GLEW_VERSION_3_0)
   {
diff --git a/build/cmake/CMakeLists.txt b/build/cmake/CMakeLists.txt
index 1ebea14..a6dbc3e 100644
--- a/build/cmake/CMakeLists.txt
+++ b/build/cmake/CMakeLists.txt
@@ -78,6 +78,10 @@ set (GLEW_SRC_FILES ${GLEW_DIR}/src/glew.c)
 
 if (WIN32)
   list (APPEND GLEW_SRC_FILES ${GLEW_DIR}/build/glew.rc)
+  if ((CMAKE_C_COMPILER_ID MATCHES "GNU") OR (CMAKE_C_COMPILER_ID MATCHES "Clang"))
+    # GCC can't handle not having a DLL entry point, so give it a fake one
+    list (APPEND GLEW_SRC_FILES ${GLEW_DIR}/src/gcc_dll_entry.c)
+  endif ()
 endif ()
 
 add_library (glew SHARED ${GLEW_SRC_FILES})
@@ -85,18 +89,21 @@ set_target_properties (glew PROPERTIES COMPILE_DEFINITIONS "GLEW_BUILD" OUTPUT_N
 add_library (glew_s STATIC ${GLEW_SRC_FILES})
 set_target_properties (glew_s PROPERTIES COMPILE_DEFINITIONS "GLEW_STATIC" OUTPUT_NAME "${GLEW_LIB_NAME}" PREFIX lib)
 if (MSVC)
-  # add options from visual studio project and remove stdlib dependency
+  # add options from visual studio project
   target_compile_definitions (glew PRIVATE "GLEW_BUILD;VC_EXTRALEAN")
   target_compile_definitions (glew_s PRIVATE "GLEW_STATIC;VC_EXTRALEAN")
+  target_link_libraries (glew PRIVATE -BASE:0x62AA0000)
   # kill security checks which are dependent on stdlib
   target_compile_options (glew PRIVATE -GS-)
   target_compile_options (glew_s PRIVATE -GS-)
-  target_link_libraries (glew PRIVATE -BASE:0x62AA0000 -nodefaultlib -noentry)
+  # remove stdlib dependency
+  target_link_libraries (glew PRIVATE -nodefaultlib -noentry)
 elseif (WIN32 AND ((CMAKE_C_COMPILER_ID MATCHES "GNU") OR (CMAKE_C_COMPILER_ID MATCHES "Clang")))
   # remove stdlib dependency on windows with GCC and Clang (for similar reasons
   # as to MSVC - to allow it to be used with any Windows compiler)
-  # not thoroughly tested yet!
-  target_link_libraries (glew PRIVATE -nostdlibs -lgcc)
+  target_compile_options (glew PRIVATE -fno-builtin -fno-stack-protector)
+  target_compile_options (glew_s PRIVATE -fno-builtin -fno-stack-protector)
+  target_link_libraries (glew PRIVATE -nostdlib)
 endif ()
 target_link_libraries (glew PUBLIC ${GLEW_LIBRARIES})
 target_link_libraries (glew_s ${GLEW_LIBRARIES})
diff --git a/src/gcc_dll_entry.c b/src/gcc_dll_entry.c
new file mode 100644
index 0000000..726f05f
--- /dev/null
+++ b/src/gcc_dll_entry.c
@@ -0,0 +1,7 @@
+#ifdef GLEW_BUILD
+#include <windows.h>
+BOOL WINAPI DllMainCRTStartup(HINSTANCE instance, DWORD reason, LPVOID reserved)
+{
+  return TRUE;
+}
+#endif
\ No newline at end of file