Ignore .s files (assembly) in compilation database

[michael-schwarz]

cpp does not generate .i files from them, but Goblint later goes looking for them, failing because it can't find them.
Needed for goblint/bench#7

[sim642]

Do you have a complete command object from a compilation database for such assembly file?

I understand that nothing meaningful for us would come out of assembly code, but I'm just surprised that whatever binary (gcc or something else?) is used to compile them accepts all the preprocessing and output arguments but doesn't actually output anything. Would've expected it to just fail at that point.

[michael-schwarz]

 {
  "directory": "/home/michael/Documents/goblint-cil/bench-ideas/openssl",
  "arguments": [
   "gcc",
   "-fPIC",
   "-pthread",
   "-m64",
   "-Wa,--noexecstack",
   "-Wall",
   "-O3",
   "-DOPENSSL_USE_NODELETE",
   "-DL_ENDIAN",
   "-DOPENSSL_PIC",
   "-DOPENSSLDIR=\"/usr/local/ssl\"",
   "-DENGINESDIR=\"/usr/local/lib64/engines-3\"",
   "-DMODULESDIR=\"/usr/local/lib64/ossl-modules\"",
   "-DOPENSSL_BUILDING_OPENSSL",
   "-DNDEBUG",
   "-c",
   "-o",
   "crypto/ec/libcrypto-shlib-ecp_nistz256-x86_64.o",
   "crypto/ec/ecp_nistz256-x86_64.s"
  ],
  "file": "crypto/ec/ecp_nistz256-x86_64.s"
 }

[sim642]

Apparently GCC does produce preprocessing output for capitalized .S, which is supposed to be preprocessed. Although being assembly we wouldn't be able to parse it anyway.

Oddly for .s with -E everything is just ignored:

Input files that don’t require compilation are ignored.

(https://gcc.gnu.org/onlinedocs/gcc/Overall-Options.html#index-E)