[profile] Don't use pragma comment linker on mingw

At least when compiling with gcc, this is not supported and will
result in errors when linking against the profiler runtime. Only
use the pragma comment linker based code with MSVC, but not with
a mingw toolchain. This also undoes D107620, which shouldn't be
relevant anymore.

Differential Revision: https://reviews.llvm.org/D108095

Author: nikic

compiler-rt/lib/profile/CMakeLists.txt

@@ -114,9 +114,6 @@ endif()
 append_list_if(COMPILER_RT_HAS_NOSTDINCXX_FLAG -nostdinc++ EXTRA_FLAGS)
 # XRay uses C++ standard library headers.
 string(REGEX REPLACE "-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
-# The Windows specific code uses a #pragma comment(linker, ...) which requires
-# -fms-extensions on MinGW targets.
-append_list_if(MINGW -fms-extensions EXTRA_FLAGS)
 
 # This appears to be a C-only warning banning the use of locals in aggregate
 # initializers. All other compilers accept this, though.

compiler-rt/lib/profile/InstrProfilingFile.c

@@ -109,7 +109,7 @@ intptr_t INSTR_PROF_PROFILE_COUNTER_BIAS_DEFAULT_VAR = 0;
 
 /* This variable is a weak external reference which could be used to detect
  * whether or not the compiler defined this symbol. */
-#if defined(_WIN32)
+#if defined(_MSC_VER)
 COMPILER_RT_VISIBILITY extern intptr_t INSTR_PROF_PROFILE_COUNTER_BIAS_VAR;
 #if defined(_M_IX86) || defined(__i386__)
 #define WIN_SYM_PREFIX "_"