[efi] Allow compiling elf2efi with clang

The clang compiler does not (and apparently will not ever) allow for
variable-length arrays within structs.

Work around this limitation by using a fixed-length array to hold the
PDB filename in the debug section.

Signed-off-by: Michael Brown <[email protected]>

src/elf2efi.c

@@ -961,7 +961,7 @@ create_debug_section ( struct pe_header *pe_header, const char *filename ) {
 	struct {
 		EFI_IMAGE_DEBUG_DIRECTORY_ENTRY debug;
 		EFI_IMAGE_DEBUG_CODEVIEW_RSDS_ENTRY rsds;
-		char name[ strlen ( filename ) + 1 ];
+		char name[32];
 	} *contents;
 
 	/* Allocate PE section */