diff --git a/configure.ac b/configure.ac
index f4bd1b0e..4d85a4e2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -429,7 +429,7 @@ AS_IF([test "x$EMSCRIPTEN" = "x"],[
   AC_CHECK_FUNCS([arc4random arc4random_buf])
   AC_CHECK_FUNCS([mmap mlock madvise mprotect explicit_bzero])
 ])
-AC_CHECK_FUNCS([posix_memalign])
+AC_CHECK_FUNCS([posix_memalign getpid])
 
 AC_SUBST([LIBTOOL_EXTRA_FLAGS])
 
diff --git a/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c b/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c
index 727261f3..595d11d9 100644
--- a/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c
+++ b/src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c
@@ -47,7 +47,7 @@ typedef struct Salsa20Random_ {
     unsigned char rnd32[16U * SALSA20_RANDOM_BLOCK_SIZE];
     uint64_t      nonce;
     size_t        rnd32_outleft;
-#ifndef _MSC_VER
+#ifdef HAVE_GETPID
     pid_t         pid;
 #endif
     int           random_data_source_fd;
@@ -279,7 +279,7 @@ randombytes_salsa20_random_stir(void)
     COMPILER_ASSERT(sizeof stream.key <= sizeof m0);
     randombytes_salsa20_random_rekey(m0);
     sodium_memzero(m0, sizeof m0);
-#ifndef _MSC_VER
+#ifdef HAVE_GETPID
     stream.pid = getpid();
 #endif
 }
@@ -287,7 +287,7 @@ randombytes_salsa20_random_stir(void)
 static void
 randombytes_salsa20_random_stir_if_needed(void)
 {
-#ifdef _MSC_VER
+#ifdef HAVE_GETPID
     if (stream.initialized == 0) {
         randombytes_salsa20_random_stir();
     }