Revert "try_compile: Honor CMAKE_<LANG>_FLAGS_<CONFIG> changes"

Revert commit v3.6.0-rc1~160^2 (try_compile: Honor
CMAKE_<LANG>_FLAGS_<CONFIG> changes, 2016-04-11).  The behavior it
introduced can break projects that depend on the lack of such behavior.
We will have to introduce a policy or other mechanism to enable the
behavior in a compatible way.  Simply revert it for now.

See issue #16174.

Help/release/3.6.rst

@@ -42,11 +42,6 @@ Commands
   commands gained support for the ``%s`` placeholder.  This is
   the number of seconds since the UNIX Epoch.
 
-* The :command:`try_compile` command source file signature now honors
-  configuration-specific flags (e.g. :variable:`CMAKE_<LANG>_FLAGS_DEBUG`)
-  in the generated test project.  Previously only the default such flags
-  for the current toolchain were used.
-
 Variables
 ---------
 

Source/cmCoreTryCompile.cxx

@@ -333,14 +333,6 @@ int cmCoreTryCompile::TryCompileCode(std::vector<std::string> const& argv,
       fprintf(fout, "set(CMAKE_%s_FLAGS \"${CMAKE_%s_FLAGS}"
                     " ${COMPILE_DEFINITIONS}\")\n",
               li->c_str(), li->c_str());
-      static std::string const cfgDefault = "DEBUG";
-      std::string const cfg =
-        !tcConfig.empty() ? cmSystemTools::UpperCase(tcConfig) : cfgDefault;
-      std::string const langFlagsCfg = "CMAKE_" + *li + "_FLAGS_" + cfg;
-      const char* flagsCfg = this->Makefile->GetDefinition(langFlagsCfg);
-      fprintf(
-        fout, "set(%s %s)\n", langFlagsCfg.c_str(),
-        cmOutputConverter::EscapeForCMake(flagsCfg ? flagsCfg : "").c_str());
     }
     switch (this->Makefile->GetPolicyStatus(cmPolicies::CMP0056)) {
       case cmPolicies::WARN:

Tests/RunCMake/try_compile/CompileFlags.cmake

@@ -1,17 +0,0 @@
-enable_language(C)
-set(CMAKE_C_FLAGS_RELEASE "-DPP_ERROR ${CMAKE_C_FLAGS_DEBUG}")
-
-#-----------------------------------------------------------------------------
-set(CMAKE_TRY_COMPILE_CONFIGURATION Release)
-try_compile(RESULT ${CMAKE_CURRENT_BINARY_DIR}
-  ${CMAKE_CURRENT_SOURCE_DIR}/src.c
-  OUTPUT_VARIABLE out
-  )
-string(REPLACE "\n" "\n  " out "  ${out}")
-if(RESULT)
-  message(FATAL_ERROR "try_compile passed but should have failed:\n${out}")
-elseif(NOT "x${out}" MATCHES "PP_ERROR is defined")
-  message(FATAL_ERROR "try_compile did not fail with PP_ERROR:\n${out}")
-else()
-  message(STATUS "try_compile with per-config flag worked as expected")
-endif()

Tests/RunCMake/try_compile/RunCMakeTest.cmake

@@ -25,7 +25,6 @@ run_cmake(TargetTypeInvalid)
 run_cmake(TargetTypeStatic)
 
 run_cmake(CMP0056)
-run_cmake(CompileFlags)
 
 if(RunCMake_GENERATOR MATCHES "Make|Ninja")
   # Use a single build tree for a few tests without cleaning.

Tests/RunCMake/try_compile/src.c

@@ -2,6 +2,3 @@ int main(void)
 {
   return 0;
 }
-#ifdef PP_ERROR
-#error PP_ERROR is defined
-#endif