Fortran: Fix submodule file names across compilers

The naming convention for submodule files varies across compilers.  Add
a table to the compiler information modules and thread the information
through to the Fortran module dependency parser.  Fill out the table for
compiler ids known to support Fortran submodules.

Fixes: #18746

Modules/Compiler/Flang-Fortran.cmake

@@ -1,6 +1,9 @@
 include(Compiler/Clang)
 __compiler_clang(Fortran)
 
+set(CMAKE_Fortran_SUBMODULE_SEP "-")
+set(CMAKE_Fortran_SUBMODULE_EXT ".mod")
+
 set(CMAKE_Fortran_PREPROCESS_SOURCE
     "<CMAKE_Fortran_COMPILER> -cpp <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
 

Modules/Compiler/GNU-Fortran.cmake

@@ -1,6 +1,9 @@
 include(Compiler/GNU)
 __compiler_gnu(Fortran)
 
+set(CMAKE_Fortran_SUBMODULE_SEP "@")
+set(CMAKE_Fortran_SUBMODULE_EXT ".smod")
+
 set(CMAKE_Fortran_PREPROCESS_SOURCE
   "<CMAKE_Fortran_COMPILER> -cpp <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> -o <PREPROCESSED_SOURCE>")
 

Modules/Compiler/Intel-Fortran.cmake

@@ -1,6 +1,9 @@
 include(Compiler/Intel)
 __compiler_intel(Fortran)
 
+set(CMAKE_Fortran_SUBMODULE_SEP "@")
+set(CMAKE_Fortran_SUBMODULE_EXT ".smod")
+
 set(CMAKE_Fortran_MODDIR_FLAG "-module ")
 set(CMAKE_Fortran_FORMAT_FIXED_FLAG "-fixed")
 set(CMAKE_Fortran_FORMAT_FREE_FLAG "-free")

Modules/Compiler/PGI-Fortran.cmake

@@ -1,6 +1,9 @@
 include(Compiler/PGI)
 __compiler_pgi(Fortran)
 
+set(CMAKE_Fortran_SUBMODULE_SEP "-")
+set(CMAKE_Fortran_SUBMODULE_EXT ".mod")
+
 set(CMAKE_Fortran_PREPROCESS_SOURCE
   "<CMAKE_Fortran_COMPILER> -Mpreprocess <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
 

Modules/Compiler/XL-Fortran.cmake

@@ -1,6 +1,9 @@
 include(Compiler/XL)
 __compiler_xl(Fortran)
 
+set(CMAKE_Fortran_SUBMODULE_SEP "_")
+set(CMAKE_Fortran_SUBMODULE_EXT ".smod")
+
 set(CMAKE_Fortran_FORMAT_FIXED_FLAG "-qfixed") # [=<right_margin>]
 set(CMAKE_Fortran_FORMAT_FREE_FLAG "-qfree") # [=f90|ibm]