Fix TSAN build for fbcode

Summary:
TSAN builds for gcc 4.9 need a PIC version of the libraries
taken from the fbcode platform.  This is accomplished by assuming every
.a has a _pic.a sibling, and by fixing the third-party2 zlib build.

Test Plan: make COMPILE_WITH_TSAN=1 check

Reviewers: sdong, igor

Reviewed By: igor

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D50331

Makefile

@@ -155,8 +155,10 @@ ifdef COMPILE_WITH_TSAN
 	EXEC_LDFLAGS += -fsanitize=thread -pie
 	PLATFORM_CCFLAGS += -fsanitize=thread -fPIC -DROCKSDB_TSAN_RUN
 	PLATFORM_CXXFLAGS += -fsanitize=thread -fPIC -DROCKSDB_TSAN_RUN
-        # Turn off -pg when enabling TSAN testing, because that induces
-        # a link failure.  TODO: find the root cause
+	# Use PIC versions of any precompiled libraries
+	EXEC_LDFLAGS := $(shell echo "$(EXEC_LDFLAGS)" | sed -e 's/[.]a /_pic.a /g')
+	# Turn off -pg when enabling TSAN testing, because that induces
+	# a link failure.  TODO: find the root cause
 	pg =
 else
 	pg = -pg

build_tools/fbcode_config.sh

@@ -30,8 +30,8 @@ CFLAGS+=" -DSNAPPY"
 
 if test -z $PIC_BUILD; then
   # location of zlib headers and libraries
-  ZLIB_INCLUDE=" -I /mnt/gvfs/third-party2/zlib/feb983d9667f4cf5e9da07ce75abc824764b67a1/1.2.8/gcc-4.9-glibc-2.20/4230243/include/"
-  ZLIB_LIBS=" /mnt/gvfs/third-party2/zlib/feb983d9667f4cf5e9da07ce75abc824764b67a1/1.2.8/gcc-4.9-glibc-2.20/4230243/lib/libz.a"
+  ZLIB_INCLUDE=" -I /mnt/gvfs/third-party2/zlib/bdbc7c65a775f6b1c6ae43d677b1d380720dba7c/1.2.8/gcc-4.9-glibc-2.20/e9936bf/include/"
+  ZLIB_LIBS=" /mnt/gvfs/third-party2/zlib/bdbc7c65a775f6b1c6ae43d677b1d380720dba7c/1.2.8/gcc-4.9-glibc-2.20/e9936bf/lib/libz.a"
   CFLAGS+=" -DZLIB"
 
   # location of bzip headers and libraries