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, 22 insertions, 8 deletions

diff --git a/libgcompat/pthread.c b/libgcompat/pthread.c
index ddfc570..4ebbe6b 100644
--- a/libgcompat/pthread.c
+++ b/libgcompat/pthread.c
@@ -1,15 +1,29 @@
 #include <pthread.h>
 
-int __register_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void)) {
-	return pthread_atfork(prepare, parent, child);
-}
-
-int register_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void)) __attribute__ ((weak, alias("__register_atfork")));
+#include "alias.h" /* weak_alias */
 
-
-void __pthread_register_cancel(void *buf) {
+/**
+ * Underlying function for pthread_cleanup_push.
+ */
+void __pthread_register_cancel(void *buf)
+{
 }
 
+/**
+ * Underlying function for pthread_cleanup_push.
+ */
+void __pthread_unregister_cancel(void *buf)
+{
+}
 
-void __pthread_unregister_cancel(void *buf) {
+/**
+ * Register fork handlers.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---register-atfork.html
+ */
+int __register_atfork(void (*prepare)(void), void (*parent)(void),
+                      void (*child)(void), void *__dso_handle)
+{
+	return pthread_atfork(prepare, parent, child);
 }
+weak_alias(__register_atfork, register_atfork);