Merge branch 'patch-1' into 'master'

Clean up everything and add lots of new functions

I hope everything here is okay. I fixed some bugs in existing functions (mostly wrong prototypes or off-by-one errors) and formatted everything to a consistent style. If you'd like me to adjust the style, that's no problem. It wasn't very consistent to start with (within the code, and compared to the documentation).

*I added specific notes you may want to comment on to some of the commit messages.*

Major features:
* Pass correct `argv[0]` in loader
* Intercept `readlink("/proc/self/exe")` to allow re-exec
* Add almost all reasonable-to-implement functions in LSB 5.0.0 core generic libc. Remaining functions are:
  - Impossible-to-implement: sigreturn
  - Not useful: reentrant random (`*rand48_r`, etc.), argz, envz, pmap, rpc (clnt_*, svc*, xdr*), bindresvport
  - Got tired of it: checked wchar
* Add additional functions used by android and its NDK tools (clang, cmake, lldb, ninja, etc.).

At this point, I am able to run Android Studio with the bundled prebuilt JDK, and compile, install, and run an android application (including one with native libraries) on a real device, with only a few minor issues:
* must export `LD_LIBRARY_PATH=/opt/android-studio/jre/jre/lib/amd64/server` because musl and glibc interpret the variable differently with regards to `dlopen`. This is something that has to be patched in musl builds of openjdk, so it's not a gcompat issue.
* ld.bfd fails to parse the argument `--sysroot=/path`, but can parse `--sysroot /path`. So there's some difference with `getopt_long_only` (or getopt in general). May be a bug, may be just an API difference. May be it can be patched up.
* LLDB fails to connect to the android phone for native debugging -- I haven't tried it on glibc yet, so it may not be a gcompat issue at all (may be a phone or the app issue).

I'd be happy to send some documentation later.

See merge request !1

1 files changed, 27 insertions, 0 deletions

diff --git a/libgcompat/error.c b/libgcompat/error.c
new file mode 100644
index 0000000..c759b19
--- /dev/null
+++ b/libgcompat/error.c
@@ -0,0 +1,27 @@
+#define _GNU_SOURCE /* program_invocation_name */
+#include <errno.h>  /* program_invocation_name */
+#include <stdarg.h> /* va_list, va_start, va_end */
+#include <stdio.h>  /* fflush, fputc, fputs, stderr, stdout, vfprintf */
+#include <string.h> /* strerror */
+
+/**
+ * Print an error message.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-error-n.html
+ */
+void error(int status, int errnum, const char *format, ...)
+{
+	va_list ap;
+
+	fflush(stdout);
+	fputs(program_invocation_name, stderr);
+	fputs(": ", stderr);
+	va_start(ap, format);
+	vfprintf(stderr, format, ap);
+	va_end(ap);
+	if (errnum != 0) {
+		fputs(": ", stderr);
+		fputs(strerror(errnum), stderr);
+		fputc('\n', stderr);
+	}
+}