Support 32-bit ARM vdso.

Linux 4.1 added this.

Bug: http://b/19198045
Change-Id: I28be802ff403a61dd6733a001411b3ff05fef5a5
diff --git a/libc/SYSCALLS.TXT b/libc/SYSCALLS.TXT
index 0c59c92..5188b6d 100644
--- a/libc/SYSCALLS.TXT
+++ b/libc/SYSCALLS.TXT
@@ -350,7 +350,7 @@
 int     __set_thread_area:set_thread_area(void*) x86
 
 # vdso stuff.
-int clock_gettime(clockid_t, timespec*)                 arm,mips,mips64
-int __clock_gettime:clock_gettime(clockid_t, timespec*) arm64,x86,x86_64
-int gettimeofday(timeval*, timezone*)                   arm,mips,mips64
-int __gettimeofday:gettimeofday(timeval*, timezone*)    arm64,x86,x86_64
+int clock_gettime(clockid_t, timespec*)                 mips,mips64
+int __clock_gettime:clock_gettime(clockid_t, timespec*) arm,arm64,x86,x86_64
+int gettimeofday(timeval*, timezone*)                   mips,mips64
+int __gettimeofday:gettimeofday(timeval*, timezone*)    arm,arm64,x86,x86_64
diff --git a/libc/arch-arm/syscalls/clock_gettime.S b/libc/arch-arm/syscalls/__clock_gettime.S
similarity index 87%
rename from libc/arch-arm/syscalls/clock_gettime.S
rename to libc/arch-arm/syscalls/__clock_gettime.S
index 61a95dd..30eff03 100644
--- a/libc/arch-arm/syscalls/clock_gettime.S
+++ b/libc/arch-arm/syscalls/__clock_gettime.S
@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(clock_gettime)
+ENTRY(__clock_gettime)
     mov     ip, r7
     .cfi_register r7, ip
     ldr     r7, =__NR_clock_gettime
@@ -13,4 +13,4 @@
     bxls    lr
     neg     r0, r0
     b       __set_errno_internal
-END(clock_gettime)
+END(__clock_gettime)
diff --git a/libc/arch-arm/syscalls/gettimeofday.S b/libc/arch-arm/syscalls/__gettimeofday.S
similarity index 88%
rename from libc/arch-arm/syscalls/gettimeofday.S
rename to libc/arch-arm/syscalls/__gettimeofday.S
index f5ed674..de0eca5 100644
--- a/libc/arch-arm/syscalls/gettimeofday.S
+++ b/libc/arch-arm/syscalls/__gettimeofday.S
@@ -2,7 +2,7 @@
 
 #include <private/bionic_asm.h>
 
-ENTRY(gettimeofday)
+ENTRY(__gettimeofday)
     mov     ip, r7
     .cfi_register r7, ip
     ldr     r7, =__NR_gettimeofday
@@ -13,4 +13,4 @@
     bxls    lr
     neg     r0, r0
     b       __set_errno_internal
-END(gettimeofday)
+END(__gettimeofday)
diff --git a/libc/bionic/vdso.cpp b/libc/bionic/vdso.cpp
index 029c148..f3d95ca 100644
--- a/libc/bionic/vdso.cpp
+++ b/libc/bionic/vdso.cpp
@@ -17,7 +17,7 @@
 #include "private/bionic_globals.h"
 #include "private/bionic_vdso.h"
 
-#if defined(__aarch64__) || defined(__x86_64__) || defined (__i386__)
+#if defined(__aarch64__) || defined(__arm__) || defined(__i386__) || defined(__x86_64__)
 
 #include <limits.h>
 #include <link.h>
@@ -28,6 +28,8 @@
 #include <unistd.h>
 #include "private/KernelArgumentBlock.h"
 
+#define AT_SYSINFO_EHDR 33 /* until we have new enough uapi headers... */
+
 int clock_gettime(int clock_id, timespec* tp) {
   auto vdso_clock_gettime = reinterpret_cast<decltype(&clock_gettime)>(
     __libc_globals->vdso[VDSO_CLOCK_GETTIME].fn);
diff --git a/libc/private/bionic_vdso.h b/libc/private/bionic_vdso.h
index 5400de5..8fd0743 100644
--- a/libc/private/bionic_vdso.h
+++ b/libc/private/bionic_vdso.h
@@ -25,6 +25,7 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+
 #ifndef _PRIVATE_BIONIC_VDSO_H
 #define _PRIVATE_BIONIC_VDSO_H
 
@@ -33,7 +34,7 @@
 #if defined(__aarch64__)
 #define VDSO_CLOCK_GETTIME_SYMBOL "__kernel_clock_gettime"
 #define VDSO_GETTIMEOFDAY_SYMBOL  "__kernel_gettimeofday"
-#elif defined(__x86_64__) || defined(__i386__)
+#elif defined(__arm__) || defined(__i386__) || defined(__x86_64__)
 #define VDSO_CLOCK_GETTIME_SYMBOL "__vdso_clock_gettime"
 #define VDSO_GETTIMEOFDAY_SYMBOL  "__vdso_gettimeofday"
 #endif