[sysprof] build: fix build with explicit includes

[Christian Hergert <chergert src gnome org>]

commit 52a21ff36e60aa76e0eef708bb7fe30fed94aba4
Author: Christian Hergert <chergert redhat com>
Date:   Sat May 18 20:21:11 2019 -0700

    build: fix build with explicit includes

 src/libsysprof-ui/sysprof-environ.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/libsysprof-ui/sysprof-environ.c b/src/libsysprof-ui/sysprof-environ.c
index a87eeb1..a1200d4 100644
--- a/src/libsysprof-ui/sysprof-environ.c
+++ b/src/libsysprof-ui/sysprof-environ.c
@@ -22,6 +22,8 @@
 
 #include "config.h"
 
+#include <string.h>
+
 #include "sysprof-environ.h"
 #include "sysprof-environ-variable.h"