Cleanup of "extern char **environ" declaration

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@327904 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/sanitizer_common/sanitizer_linux.cc b/lib/sanitizer_common/sanitizer_linux.cc
index 131f2b7..dc616d7 100644
--- a/lib/sanitizer_common/sanitizer_linux.cc
+++ b/lib/sanitizer_common/sanitizer_linux.cc
@@ -85,13 +85,11 @@
 #include <sys/umtx.h>
 }
 #include <sys/thr.h>
-extern char **environ;  // provided by crt1
 #endif  // SANITIZER_FREEBSD
 
 #if SANITIZER_NETBSD
 #include <limits.h>  // For NAME_MAX
 #include <sys/sysctl.h>
-extern char **environ;  // provided by crt1
 #include <sys/exec.h>
 extern struct ps_strings *__ps_strings;
 #endif  // SANITIZER_NETBSD
@@ -99,15 +97,17 @@
 #if SANITIZER_SOLARIS
 #include <stdlib.h>
 #include <thread.h>
-
-extern char **_environ;
-#define environ _environ
 #endif
 
 #if !SANITIZER_ANDROID
 #include <sys/signal.h>
 #endif
 
+#if SANITIZER_SOLARIS
+#define environ _environ
+#endif
+extern char **_environ;
+
 #if SANITIZER_LINUX
 // <linux/time.h>
 struct kernel_timeval {