Include process.h in portability/Unistd.h

Summary: In newer versions of the windows STL, this gets included in <thread>, so explicitly include it in Unistd.h and remove the definition of getpid.

Reviewed By: yfeldblum

Differential Revision: D23498073

fbshipit-source-id: 5fe07dbbaa9fb1bf5c904286bd15beccbf1d1615

folly/portability/Unistd.cpp

@@ -119,10 +119,6 @@ int getgid() {
   return 1;
 }
 
-pid_t getpid() {
-  return (pid_t)uint64_t(GetCurrentProcessId());
-}
-
 // No major need to implement this, and getting a non-potentially
 // stale ID on windows is a bit involved.
 pid_t getppid() {

folly/portability/Unistd.h

@@ -24,6 +24,8 @@
 
 #include <cstdint>
 
+#include <process.h> // @manual
+
 #include <sys/locking.h> // @manual
 
 #include <folly/Portability.h>
@@ -69,7 +71,6 @@ int ftruncate(int fd, off_t len);
 char* getcwd(char* buf, int sz);
 int getdtablesize();
 int getgid();
-pid_t getpid();
 pid_t getppid();
 int getuid();
 int isatty(int fh);