MDEV-9943 - TokuDB fails to compile with gcc 5.2.1

For some reason check_cxx_compiler_flag() passes result variable name down to
compiler:
https://github.com/Kitware/CMake/blob/master/Modules/CheckCXXSourceCompiles.cmake#L57

But compiler doesn't permit dashes in macro name, like in
-DHAVE_CXX_-fimplicit-templates.

Workarounded by renaming HAVE_CXX_-fimplicit-templates to
HAVE_CXX_IMPLICIT_TEMPLAES.

storage/tokudb/ft-index/cmake_modules/TokuSetupCompiler.cmake

@@ -61,12 +61,13 @@ endmacro(set_cflags_if_supported_named)
 ## adds a compiler flag if the compiler supports it
 macro(set_cflags_if_supported)
   foreach(flag ${ARGN})
-    check_c_compiler_flag(${flag} HAVE_C_${flag})
-    if (HAVE_C_${flag})
+    STRING(REGEX REPLACE "[-,= ]" "_" res ${flag})
+    check_c_compiler_flag(${flag} HAVE_C_${res})
+    if (HAVE_C_${res})
       set(CMAKE_C_FLAGS "${flag} ${CMAKE_C_FLAGS}")
     endif ()
-    check_cxx_compiler_flag(${flag} HAVE_CXX_${flag})
-    if (HAVE_CXX_${flag})
+    check_cxx_compiler_flag(${flag} HAVE_CXX_${res})
+    if (HAVE_CXX_${res})
       set(CMAKE_CXX_FLAGS "${flag} ${CMAKE_CXX_FLAGS}")
     endif ()
   endforeach(flag)
@@ -75,8 +76,9 @@ endmacro(set_cflags_if_supported)
 ## adds a linker flag if the compiler supports it
 macro(set_ldflags_if_supported)
   foreach(flag ${ARGN})
-    check_cxx_compiler_flag(${flag} HAVE_${flag})
-    if (HAVE_${flag})
+    STRING(REGEX REPLACE "[-,= ]" "_" res ${flag})
+    check_cxx_compiler_flag(${flag} HAVE_${res})
+    if (HAVE_${res})
       set(CMAKE_EXE_LINKER_FLAGS "${flag} ${CMAKE_EXE_LINKER_FLAGS}")
       set(CMAKE_SHARED_LINKER_FLAGS "${flag} ${CMAKE_SHARED_LINKER_FLAGS}")
     endif ()
@@ -103,8 +105,8 @@ set_cflags_if_supported(
 
 if (CMAKE_CXX_FLAGS MATCHES -fno-implicit-templates)
   # must append this because mysql sets -fno-implicit-templates and we need to override it
-  check_cxx_compiler_flag(-fimplicit-templates HAVE_CXX_-fimplicit-templates)
-  if (HAVE_CXX_-fimplicit-templates)
+  check_cxx_compiler_flag(-fimplicit-templates HAVE_CXX_IMPLICIT_TEMPLATES)
+  if (HAVE_CXX_IMPLICIT_TEMPLATES)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fimplicit-templates")
   endif ()
 endif()