While GNU as only allows the directory form of the .file directive for DWARF v5,
the integrated assembler prefers the directory form on all DWARF versions
(-fdwarf-directory-asm).
We currently set CC1 -fno-dwarf-directory-asm for -fno-integrated-as -gdwarf-5
which may cause the directory entry 0 and the filename entry 0 to be incorrect
(see D105662 and the example below). This patch makes -fno-integrated-as -gdwarf-5 use
-fdwarf-directory-asm as well.
```
cd /tmp/c
before
% clang -g -gdwarf-5 -fno-integrated-as e/a.c -S -o - | grep '\.file.*0'
.file 0 "/tmp/c/e/a.c" md5 0x97e31cee64b4e58a4af8787512d735b6
% clang -g -gdwarf-5 -fno-integrated-as e/a.c -c
% llvm-dwarfdump a.o | grep include_directories
include_directories[ 0] = "/tmp/c/e"
after
% clang -g -gdwarf-5 -fno-integrated-as e/a.c -S -o - | grep '\.file.*0'
.file 0 "/tmp/c" "e/a.c" md5 0x97e31cee64b4e58a4af8787512d735b6
% clang -g -gdwarf-5 -fno-integrated-as e/a.c -c
% llvm-dwarfdump a.o | grep include_directories
include_directories[ 0] = "/tmp/c"
```
Reviewed By: #debug-info, dblaikie, osandov
Differential Revision: https://reviews.llvm.org/D105835
51fc742ce7