[benchmark] Fix win32 link on case-sensitive fs

Summary: This fixes cross-builds with MinGW from case-sensitive file-systems (on Linux)

This is a cherry-pick from
https://github.com/google/benchmark/pull/840
8e48105d46

Original patch by: @jschueller (Julien Schueller) !

Differential Revision: https://reviews.llvm.org/D61371

llvm-svn: 367356

utils/benchmark/README.LLVM

@@ -25,3 +25,5 @@ Changes:
   and hardcoded a null version
 * https://github.com/google/benchmark/commit/4abdfbb802d1b514703223f5f852ce4a507d32d2
   is applied on top of v1.4.1 to add RISC-V timer support.
+* https://github.com/google/benchmark/commit/8e48105d465c586068dd8e248fe75a8971c6ba3a
+  is applied on top of v1.4.1 to fix cross-build from linux to windows via MinGW.

utils/benchmark/src/CMakeLists.txt

@@ -36,7 +36,7 @@ endif()
 
 # We need extra libraries on Windows
 if(${CMAKE_SYSTEM_NAME} MATCHES "Windows")
-  target_link_libraries(benchmark Shlwapi)
+  target_link_libraries(benchmark shlwapi)
 endif()
 
 # We need extra libraries on Solaris