Merge pull request #253 from TimothyGu/patch-1

Install pkg-config file on MinGW systems as well

CMakeLists.txt

@@ -288,14 +288,14 @@ IF(INSTALL_LIBS)
 	## the following are directories where stuff will be installed to
 	SET(INCLUDE_INSTALL_DIR      "include/bullet/" CACHE PATH "The subdirectory to the header prefix")
 	SET(PKGCONFIG_INSTALL_PREFIX "lib${LIB_SUFFIX}/pkgconfig/" CACHE STRING "Base directory for pkgconfig files")
-	IF(NOT WIN32)
+	IF(NOT MSVC)
 	  CONFIGURE_FILE(${CMAKE_CURRENT_SOURCE_DIR}/bullet.pc.cmake ${CMAKE_CURRENT_BINARY_DIR}/bullet.pc @ONLY)
   	INSTALL(
 	    FILES
     	${CMAKE_CURRENT_BINARY_DIR}/bullet.pc
     	DESTINATION
     	${PKGCONFIG_INSTALL_PREFIX})
-	ENDIF(NOT WIN32)
+	ENDIF(NOT MSVC)
 ENDIF(INSTALL_LIBS)
 
 #INSTALL of other files requires CMake 2.6