linker: add dlvsym(3)

This changes implements dlvsym - dlsym for versioned symbols.

Bug: http://b/22865643
Change-Id: Ic90a60d512104261a1416c43f9100f0d88e3b46f

libdl/libdl.arm.map

@@ -18,6 +18,7 @@ LIBC_N {
   global:
     android_init_namespaces;
     android_create_namespace;
+    dlvsym;
 } LIBC;
 
 LIBC_PRIVATE {

libdl/libdl.arm64.map

@@ -17,6 +17,7 @@ LIBC_N {
   global:
     android_init_namespaces;
     android_create_namespace;
+    dlvsym;
 } LIBC;
 
 LIBC_PRIVATE {

libdl/libdl.c

@@ -24,9 +24,17 @@
 // in the dynamic linker and hijacked at runtime.
 
 void* dlopen(const char* filename __unused, int flag __unused) { return 0; }
+
 const char* dlerror(void) { return 0; }
+
 void* dlsym(void* handle __unused, const char* symbol __unused) { return 0; }
+
+void* dlvsym(void* handle __unused, const char* symbol __unused, const char* version __unused) {
+  return 0;
+}
+
 int dladdr(const void* addr __unused, Dl_info* info __unused) { return 0; }
+
 int dlclose(void* handle __unused) { return 0; }
 
 #if defined(__arm__)

libdl/libdl.map.txt

@@ -32,6 +32,7 @@ LIBC_N {
   global:
     android_init_namespaces;
     android_create_namespace;
+    dlvsym;
 } LIBC;
 
 LIBC_PRIVATE {

libdl/libdl.mips.map

@@ -17,6 +17,7 @@ LIBC_N {
   global:
     android_init_namespaces;
     android_create_namespace;
+    dlvsym;
 } LIBC;
 
 LIBC_PRIVATE {

libdl/libdl.mips64.map

@@ -17,6 +17,7 @@ LIBC_N {
   global:
     android_init_namespaces;
     android_create_namespace;
+    dlvsym;
 } LIBC;
 
 LIBC_PRIVATE {

libdl/libdl.x86.map

@@ -17,6 +17,7 @@ LIBC_N {
   global:
     android_init_namespaces;
     android_create_namespace;
+    dlvsym;
 } LIBC;
 
 LIBC_PRIVATE {

libdl/libdl.x86_64.map

@@ -17,6 +17,7 @@ LIBC_N {
   global:
     android_init_namespaces;
     android_create_namespace;
+    dlvsym;
 } LIBC;
 
 LIBC_PRIVATE {