Clean up the linker a bit, remove prelinking support.

Also make the errors more readable, since none of us seemed to know
what they actually meant. The new style is still as verbose as the
old, but that's probably necessary in the absence of chained exceptions
in C. Here's what you'd see if you try to boot after removing
libsurfaceflinger.so:

  32267 32267 E AndroidRuntime: java.lang.UnsatisfiedLinkError: Cannot load library: (linker.c:1629, pid 32259) soinfo_link_image: could not load library "libsystem_server.so" needed by "libandroid_servers.so"; caused by (linker.c:1629, pid 32259) soinfo_link_image: could not load library "libsurfaceflinger.so" needed by "libsystem_server.so"; caused by (linker.c:709, pid 32259) load_library: library "libsurfaceflinger.so" not found

This patch also fixes almost all of the compiler warnings.

Change-Id: I64bb59aed6d4e039c15ea45be2367f319ef879f8

linker/linker.h

@@ -34,6 +34,10 @@
 #include <elf.h>
 #include <sys/exec_elf.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #undef PAGE_MASK
 #undef PAGE_SIZE
 #define PAGE_SIZE 4096
@@ -106,7 +110,7 @@ typedef struct soinfo soinfo;
 
 struct soinfo
 {
-    const char name[SOINFO_NAME_LEN];
+    char name[SOINFO_NAME_LEN];
     const Elf32_Phdr *phdr;
     int phnum;
     unsigned entry;
@@ -244,4 +248,8 @@ _Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc, int *pcount);
 int dl_iterate_phdr(int (*cb)(struct dl_phdr_info *, size_t, void *), void *);
 #endif
 
+#ifdef __cplusplus
+};
+#endif
+
 #endif