gdb: Change default solib search path

Add /system/lib(64) and /system/vendor/lib(64) to the default
solib search path so that system shared libraries are found.

Error mentioned in issue #73.

packages/gdb/build.sh

@@ -2,6 +2,7 @@ TERMUX_PKG_HOMEPAGE=https://www.gnu.org/software/gdb/
 TERMUX_PKG_DESCRIPTION="The standard GNU Debugger that runs on many Unix-like systems and works for many programming languages"
 TERMUX_PKG_DEPENDS="liblzma, libexpat, readline"
 TERMUX_PKG_VERSION=7.10.1
+TERMUX_PKG_BUILD_REVISION=1
 TERMUX_PKG_SRCURL=http://ftp.gnu.org/gnu/gdb/gdb-${TERMUX_PKG_VERSION}.tar.xz
 # gdb can not build with our normal --disable-static: https://sourceware.org/bugzilla/show_bug.cgi?id=15916
 TERMUX_PKG_EXTRA_CONFIGURE_ARGS="--with-system-readline --with-curses --enable-static ac_cv_func_getpwent=no ac_cv_func_getpwnam=no"

packages/gdb/gdb-solib.c.patch

@@ -0,0 +1,20 @@
+diff -u -r ../gdb-7.10.1/gdb/solib.c ./gdb/solib.c
+--- ../gdb-7.10.1/gdb/solib.c	2015-12-05 10:16:45.000000000 -0500
++++ ./gdb/solib.c	2016-02-07 17:29:11.431584611 -0500
+@@ -1703,6 +1703,16 @@
+   add_alias_cmd ("solib-absolute-prefix", "sysroot", class_support, 0,
+ 		 &showlist);
+ 
++#ifdef __ANDROID__
++  /* Termux modification to find system shared libraries. */
++  solib_search_path =
++# ifdef __LP64__
++    "/system/lib64:/system/vendor/lib64";
++# else
++    "/system/lib:/system/vendor/lib";
++# endif
++#endif
++
+   add_setshow_optional_filename_cmd ("solib-search-path", class_support,
+ 				     &solib_search_path, _("\
+ Set the search path for loading non-absolute shared library symbol files."),