diff --git a/src/pmwebapi/pmgraphite.cxx b/src/pmwebapi/pmgraphite.cxx
index 5c0c166..cf93a4d 100644
--- a/src/pmwebapi/pmgraphite.cxx
+++ b/src/pmwebapi/pmgraphite.cxx
@@ -1456,7 +1459,7 @@ float nicenum (float x, bool round_p)
     double nf;/* nice, rounded fraction */
 
     expv = (int) floor (log10f (x));
-    f = x/exp10f (expv); /* between 1 and 10 */
+    f = x/powf (10., expv); /* between 1 and 10 */
     if (round_p)
         if (f<1.5) {
             nf = 1.;
@@ -1476,7 +1479,7 @@ float nicenum (float x, bool round_p)
     } else {
         nf = 10.;
     }
-    return nf*exp10f (expv);
+    return nf*powf (10., expv);
 }
 
 vector<float> round_linear (float& ymin, float& ymax, unsigned nticks)
@@ -1733,9 +1736,9 @@ pmgraphite_respond_render_gfx (struct MHD_Connection *connection,
 
     // What makes us tick?
     yticks = round_linear (ymin, ymax,
-                           (unsigned) (0.3 * sqrt (height))); // flot heuristic
+                           (unsigned) (0.3 * sqrtf (height))); // flot heuristic
     xticks = round_time (t_start, t_end,
-                         (unsigned) (0.3 * sqrt (width)), // flot heuristic
+                         (unsigned) (0.3 * sqrtf (width)), // flot heuristic
                          & strf_format);
 
 
diff --git a/src/pmwebapi/pmresapi.cxx b/src/pmwebapi/pmresapi.cxx
index 03d64c7..d4cedad 100644
--- a/src/pmwebapi/pmresapi.cxx
+++ b/src/pmwebapi/pmresapi.cxx
@@ -31,7 +31,7 @@ using namespace std;
 static const char *
 guess_content_type (const char *filename)
 {
-    const char *extension = rindex (filename, '.');
+    const char *extension = strrchr (filename, '.');
     if (extension == NULL) {
         return NULL;
     }
diff --git a/src/pmwebapi/util.cxx b/src/pmwebapi/util.cxx
index 82524f0..ed5b85e 100644
--- a/src/pmwebapi/util.cxx
+++ b/src/pmwebapi/util.cxx
@@ -12,7 +12,7 @@
  * for more details.
  */
 
-#define _XOPEN_SOURCE 500
+#define _XOPEN_SOURCE 600
 
 #include "pmapi.h"
 #include "impl.h"