FortranCInterface: Fix mangling detection with Cray Fortran >= 7.3.2

The Cray Fortran compiler started using module init symbols in version 7.3.2.
Starting in commit 71287734 (Teach FortranC interface for Intel, PGI, and gcc
4.2, 2009-08-05) we provide C versions of the module init symbols so that the
detection executable can link when the C versions of the module-mangled symbols
are picked up.

If no C module-mangled symbol matches then we cannot let the C module init
symbol appear because it will be duplicated by the Fortran copy that provides
the module-mangled symbol.  This was first handled for the PathScale compiler
in commit 21faaa5d (FortranCInterface: Fix PathScale detection, 2010-01-22) and
commit 46858720 (FortranCInterface: Fix PathScale detection again, 2010-02-16).
Handle it now for the Cray compiler too.

Modules/FortranCInterface/CMakeLists.txt

@@ -70,6 +70,17 @@ else()
 endif()
 
 # Generate C symbol sources.
+set(symbol_sources)
+if(NOT "${CMAKE_Fortran_COMPILER_ID}" MATCHES "^(PathScale|Cray)$")
+  # Provide mymodule_ and my_module_ init symbols because:
+  #  - PGI Fortran uses module init symbols
+  # but not for:
+  #  - PathScale Fortran uses module init symbols but module symbols
+  #    use '.in.' so we cannot provide them anyway.
+  #  - Cray Fortran >= 7.3.2 uses module init symbols but module symbols
+  #    use 'mysub$mymodule_' so we cannot provide them anyway.
+  list(APPEND symbol_sources mymodule_.c my_module_.c)
+endif()
 foreach(symbol IN LISTS global_symbols module_symbols)
   # Skip symbols with '$' if C cannot handle them.
   if(C_SUPPORTS_DOLLAR OR NOT "${symbol}" MATCHES "\\$")
@@ -89,7 +100,7 @@ endforeach()
 add_library(myfort STATIC mysub.f my_sub.f ${myfort_modules})
 
 # Provide symbols through C but fall back to Fortran.
-add_library(symbols STATIC mymodule_.c my_module_.c ${symbol_sources})
+add_library(symbols STATIC ${symbol_sources})
 target_link_libraries(symbols myfort)
 
 # Require symbols through Fortran.

Modules/FortranCInterface/my_module_.c

@@ -1,8 +1 @@
-#if defined(__PATHSCALE__)
-/* PathScale Fortran wants my_module_ when calling any my_module symbol,
-   but module symbols use '.in.' so we cannot provide them anyway.  */
-void pathscale_my_module_(void) {}
-#else
-/* PGI Fortran wants my_module_ when calling any my_module symbol.  */
 void my_module_(void) {}
-#endif

Modules/FortranCInterface/mymodule_.c

@@ -1,8 +1 @@
-#if defined(__PATHSCALE__)
-/* PathScale Fortran wants mymodule_ when calling any mymodule symbol,
-   but module symbols use '.in.' so we cannot provide them anyway.  */
-void pathscale_mymodule_(void) {}
-#else
-/* PGI Fortran wants mymodule_ when calling any mymodule symbol.  */
 void mymodule_(void) {}
-#endif