ltrace: Fix incompatibilities with Android linker

- Find libraries in LD_LIBRARY_PATH if relative path is found in debug
  link_map
- Skip main executable
- Skip /system/bin/linker and [vdso]
- Only set proc->e_machine once, as it might be set wrongly if we later
  try to load library that we couldn't find

disabled-packages/ltrace/ltrace-elf.c.patch

@@ -1,6 +1,8 @@
---- ltrace-2def9f1217374cc8371105993003b2c663aefda7/ltrace-elf.c	2016-04-11 21:30:04.000000000 +0200
+diff --git a/ltrace-elf.c b/ltrace-elf.c
-+++ src/ltrace-elf.c	2016-05-07 21:23:17.999754862 +0200
+index f439cb0..60f1941 100644
-@@ -423,7 +423,9 @@
+--- a/ltrace-elf.c
++++ b/ltrace-elf.c
+@@ -423,7 +423,9 @@ ltelf_destroy(struct ltelf *lte)
  	debug(DEBUG_FUNCTION, "close_elf()");
  	elf_end(lte->elf);
  	close(lte->fd);
@@ -11,3 +13,18 @@
  }
  
  static void
+@@ -1149,9 +1151,11 @@ read_module(struct library *lib, struct process *proc,
+ 	 * determine whether ABI is supported.  This is to get
+ 	 * reasonable error messages when trying to run 64-bit binary
+ 	 * with 32-bit ltrace.  It is desirable to preserve this.  */
+-	proc->e_machine = lte.ehdr.e_machine;
+-	proc->e_class = lte.ehdr.e_ident[EI_CLASS];
+-	get_arch_dep(proc);
++	if (proc->e_machine == 0) {
++		proc->e_machine = lte.ehdr.e_machine;
++		proc->e_class = lte.ehdr.e_ident[EI_CLASS];
++		get_arch_dep(proc);
++	}
+ 
+ 	/* Find out the base address.  For PIE main binaries we look
+ 	 * into auxv, otherwise we scan phdrs.  */

disabled-packages/ltrace/sysdeps-linux-gnu-proc.c.patch

@@ -0,0 +1,59 @@
+diff --git a/sysdeps/linux-gnu/proc.c b/sysdeps/linux-gnu/proc.c
+index 953fd86..bdb96cb 100644
+--- a/sysdeps/linux-gnu/proc.c
++++ b/sysdeps/linux-gnu/proc.c
+@@ -524,9 +524,53 @@ crawl_linkmap(struct process *proc, struct lt_r_debug_64 *dbg)
+ 		    || strcmp(lib_name, "linux-vdso.so.1") == 0
+ 		    || strcmp(lib_name, "linux-gate.so.1") == 0
+ 		    || strcmp(lib_name, "linux-vdso32.so.1") == 0
+-		    || strcmp(lib_name, "linux-vdso64.so.1") == 0)
++		    || strcmp(lib_name, "linux-vdso64.so.1") == 0
++		    || strcmp(lib_name, "[vdso]") == 0
++		    /* Android linker includes itself in list of libraries
++		     * on GNU linker it appears as empty string */
++		    || strcmp(lib_name, "/system/bin/linker") == 0
++		    || strcmp(lib_name, "/system/bin/linker64") == 0)
+ 			continue;
+ 
++		/* On Android main executable is included in library list
++		 * On GNU it appears as empty string */
++		if (rlm.l_prev == 0 && strstr(lib_name, ".so") == NULL) {
++			continue;
++		}
++
++		/* Android < 6 provides just library name without full path,
++		 * will find full path ourselves */
++		if (lib_name[0] != '/') {
++			char local_path[1024];
++			/* Include path from LD_LIBRARY_PATH */
++			const char *path = getenv("LD_LIBRARY_PATH");
++			if (path) {
++				strlcpy(local_path, path, sizeof(local_path));
++			} else {
++				local_path[0] = '\0';
++			}
++			/* Include default path (hardcoded in /system/bin/linker) */
++			strlcat(
++					local_path,
++					select_32_64(proc, ":/vendor/lib:/system/lib", ":/vendor/lib64:/system/lib64"),
++					sizeof(local_path)
++			);
++
++			char *local_path_ptr = local_path;
++			const char *tested_path;
++			char full_lib_name[BUFSIZ];
++			while ((tested_path = strsep(&local_path_ptr, ":"))) {
++				if (tested_path[0] == '\0') {
++					continue;
++				}
++				snprintf(full_lib_name, sizeof(full_lib_name), "%s/%s", tested_path, lib_name);
++				if (access(full_lib_name, F_OK) == 0) {
++					strlcpy(lib_name, full_lib_name, sizeof(lib_name));
++					break;
++				}
++			}
++		}
++
+ 		/* Do we have that library already?  */
+ 		if (proc_each_library(proc, NULL, library_with_key_cb, &key))
+ 			continue;