FindHDF5: Fix Windows compile-line parsing

We modify the signature of _HDF5_parse_compile_line to pass the command
line variable name rather than the command line itself.  Otherwise the
CMake language MACRO implementation tries to parse the command line as
CMake syntax, which does not like backslashes.

Modules/FindHDF5.cmake

@@ -107,7 +107,7 @@ endmacro()
 
 # Parse a compile line for definitions, includes, library paths, and libraries.
 macro( _HDF5_parse_compile_line 
-    compile_line 
+    compile_line_var
     include_paths
     definitions
     library_paths
@@ -115,7 +115,7 @@ macro( _HDF5_parse_compile_line
 
     # Match the include paths
     string( REGEX MATCHALL "-I([^\" ]+)" include_path_flags 
-        "${compile_line}" 
+        "${${compile_line_var}}"
     )
     foreach( IPATH ${include_path_flags} )
         string( REGEX REPLACE "^-I" "" IPATH ${IPATH} )
@@ -124,14 +124,14 @@ macro( _HDF5_parse_compile_line
     endforeach()
 
     # Match the definitions
-    string( REGEX MATCHALL "-D[^ ]*" definition_flags "${compile_line}" )
+    string( REGEX MATCHALL "-D[^ ]*" definition_flags "${${compile_line_var}}" )
     foreach( DEF ${definition_flags} )
         list( APPEND ${definitions} ${DEF} )
     endforeach()
 
     # Match the library paths
     string( REGEX MATCHALL "-L([^\" ]+|\"[^\"]+\")" library_path_flags
-        "${compile_line}"
+        "${${compile_line_var}}"
     )
     
     foreach( LPATH ${library_path_flags} )
@@ -144,7 +144,7 @@ macro( _HDF5_parse_compile_line
     # match only -l's preceded by a space or comma
     # this is to exclude directory names like xxx-linux/
     string( REGEX MATCHALL "[, ]-l([^\", ]+)" library_name_flags
-        "${compile_line}" )
+        "${${compile_line_var}}" )
     # strip the -l from all of the library flags and add to the search list
     foreach( LIB ${library_name_flags} )
         string( REGEX REPLACE "^[, ]-l" "" LIB ${LIB} )
@@ -180,7 +180,7 @@ else()
     
     foreach( LANGUAGE ${HDF5_LANGUAGE_BINDINGS} )
         if( HDF5_${LANGUAGE}_COMPILE_LINE )
-            _HDF5_parse_compile_line( ${HDF5_${LANGUAGE}_COMPILE_LINE} 
+            _HDF5_parse_compile_line( HDF5_${LANGUAGE}_COMPILE_LINE
                 HDF5_${LANGUAGE}_INCLUDE_FLAGS
                 HDF5_${LANGUAGE}_DEFINITIONS
                 HDF5_${LANGUAGE}_LIBRARY_DIRS