1 files changed, 1 insertions, 0 deletions
diff --git a/string.c b/string.c
index 5eb5d248ed..40207e5ba4 100644
--- a/string.c
+++ b/string.c
@@ -18,6 +18,7 @@
 #define BEG(no) regs->beg[no]
 #define END(no) regs->end[no]
 
+#include <math.h>
 #include <ctype.h>
 
 #ifdef HAVE_UNISTD_H