[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

(cherry picked from commit 4cfb047)

Author: nikic

compiler-rt/lib/profile/InstrProfilingFile.c

@@ -592,7 +592,7 @@ 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;
 #pragma comment(linker, "/alternatename:"                                      \
       INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_COUNTER_BIAS_VAR) "="                \