Extend linker-script workaround to work with musl libc

GHC has code to handle unsuffixed .so files that are linker scripts
pointing to the real shared library. The detection is done by parsing
the result of `dlerror()` after calling `dlopen()` and looking for
certain error strings. On musl libc, the error message is "Exec format
error", which happens to be `strerror(ENOEXEC)`:

```
$ cat tmp.c
#include <dlfcn.h>
#include <stdio.h>

int main(void) {
        dlopen("libz.so", RTLD_NOW | RTLD_GLOBAL);
        puts(dlerror());
        return 0;
}
$ gcc -o tmp tmp.c
$ ./tmp
Error loading shared library libz.so: Exec format error
$
```

This change fixes the workaround to also work on musl libc.

Link: https://phabricator.haskell.org/D5474

1 files changed, 1 insertions, 1 deletions

diff --git a/rts/Linker.c b/rts/Linker.c
index 5b10b798ec..ac030af837 100644
--- a/rts/Linker.c
+++ b/rts/Linker.c
@@ -483,7 +483,7 @@ initLinker_ (int retain_cafs)
 #   endif /* RTLD_DEFAULT */
 
     compileResult = regcomp(&re_invalid,
-           "(([^ \t()])+\\.so([^ \t:()])*):([ \t])*(invalid ELF header|file too short|invalid file format)",
+           "(([^ \t()])+\\.so([^ \t:()])*):([ \t])*(invalid ELF header|file too short|invalid file format|Exec format error)",
            REG_EXTENDED);
     if (compileResult != 0) {
         barf("Compiling re_invalid failed");