diff --git a/src/lib/proj4lib/include/proj4.h b/src/lib/proj4lib/include/proj4.h
index 9298ccba..c6732245 100644
--- a/src/lib/proj4lib/include/proj4.h
+++ b/src/lib/proj4lib/include/proj4.h
@@ -7,6 +7,7 @@
 #ifndef PROJ4_H
 #define PROJ4_H
 
+#define _USE_MATH_DEFINES
 #include <math.h>
 #include <stdlib.h>
 /*
@@ -21,13 +22,17 @@ extern long double usgs_hypot(long double, long double);
 
 /* some useful constants */
 
-#define FORTPI     M_PI_4
-#define PI         M_PI
-#define TWOPI      6.28318530717958647692528676655900576L
+#define FORTPI M_PI_4
+#define PI M_PI
+#define TWOPI 6.28318530717958647692528676655900576L
 #define RAD_TO_DEG M_180_PI
 #define DEG_TO_RAD M_PI_180
 
-typedef union { long double f; int i; char *s; } PVALUE;
+typedef union {
+  long double f;
+  int i;
+  char *s;
+} PVALUE;
 
 /* procedure prototypes */
 
@@ -49,4 +54,3 @@ long double pj_authlat(long double, long double *);
 */
 
 #endif
-
diff --git a/src/lib/proj4lib/lib/adjlon.cpp b/src/lib/proj4lib/lib/adjlon.cpp
index 3cf84016..8877f245 100644
--- a/src/lib/proj4lib/lib/adjlon.cpp
+++ b/src/lib/proj4lib/lib/adjlon.cpp
@@ -1,16 +1,17 @@
 /* reduce argument to range +/- PI */
 #ifndef lint
-//static const char SCCSID[]="@(#)adjlon.c	4.3	93/06/12	GIE	REL";
+// static const char SCCSID[]="@(#)adjlon.c	4.3	93/06/12	GIE
+// REL";
 #endif
+#define _USE_MATH_DEFINES
 #include <math.h>
 /* note: PI adjusted high
 ** approx. true val:	3.14159265358979323844
 */
-#define SPI		3.14159265359
-#define TWOPI	6.2831853071795864769
-	long double
-adjlon (long double lon) {
-	while ( fabsl(lon) > SPI )
-		lon += lon < 0. ? TWOPI : -TWOPI;
-	return( lon );
+#define SPI 3.14159265359
+#define TWOPI 6.2831853071795864769
+long double adjlon(long double lon) {
+  while (fabsl(lon) > SPI)
+    lon += lon < 0. ? TWOPI : -TWOPI;
+  return (lon);
 }
diff --git a/src/lib/proj4lib/lib/pj_phi2.cpp b/src/lib/proj4lib/lib/pj_phi2.cpp
index 564a99bd..bb7dd426 100644
--- a/src/lib/proj4lib/lib/pj_phi2.cpp
+++ b/src/lib/proj4lib/lib/pj_phi2.cpp
@@ -1,29 +1,30 @@
 /* determine latitude angle phi-2 */
 #ifndef lint
-//static const char SCCSID[]="@(#)pj_phi2.c	4.3	93/06/12	GIE	REL";
+// static const char SCCSID[]="@(#)pj_phi2.c	4.3	93/06/12	GIE
+// REL";
 #endif
 #include "proj4.h"
+#define _USE_MATH_DEFINES
+#include <math.h>
 
 #define TOL 1.0e-10
 #define N_ITER 15
 
-	long double
-pj_phi2(long double ts, long double e) {
-	long double eccnth, Phi, con, dphi;
-	int i;
+long double pj_phi2(long double ts, long double e) {
+  long double eccnth, Phi, con, dphi;
+  int i;
 
-	eccnth = .5 * e;
-	Phi = M_PI_2 - 2. * atan (ts);
-	i = N_ITER;
-	do {
-		con = e * sin (Phi);
-		dphi = M_PI_2 - 2. * atan (ts * pow((1. - con) /
-		   (1. + con), eccnth)) - Phi;
-		Phi += dphi;
-	} while ( fabsl(dphi) > TOL && --i);
-/*
-	if (i <= 0)
-		pj_errno = -18;
-*/
-	return Phi;
+  eccnth = .5 * e;
+  Phi = M_PI_2 - 2. * atan(ts);
+  i = N_ITER;
+  do {
+    con = e * sin(Phi);
+    dphi = M_PI_2 - 2. * atan(ts * pow((1. - con) / (1. + con), eccnth)) - Phi;
+    Phi += dphi;
+  } while (fabsl(dphi) > TOL && --i);
+  /*
+          if (i <= 0)
+                  pj_errno = -18;
+  */
+  return Phi;
 }
diff --git a/src/lib/proj4lib/lib/pj_qsfn.cpp b/src/lib/proj4lib/lib/pj_qsfn.cpp
index fc8d50e4..3a265684 100644
--- a/src/lib/proj4lib/lib/pj_qsfn.cpp
+++ b/src/lib/proj4lib/lib/pj_qsfn.cpp
@@ -1,18 +1,19 @@
 /* determine small q */
 #ifndef lint
-//static const char SCCSID[]="@(#)pj_qsfn.c	4.3	93/06/12	GIE	REL";
+// static const char SCCSID[]="@(#)pj_qsfn.c	4.3	93/06/12	GIE
+// REL";
 #endif
+#define _USE_MATH_DEFINES
 #include <math.h>
 
-# define EPSILON 1.0e-7
-	long double
-pj_qsfn(long double sinphi, long double e, long double one_es) {
-	long double con;
+#define EPSILON 1.0e-7
+long double pj_qsfn(long double sinphi, long double e, long double one_es) {
+  long double con;
 
-	if (e >= EPSILON) {
-		con = e * sinphi;
-		return (one_es * (sinphi / (1. - con * con) -
-		   (.5 / e) * log ((1. - con) / (1. + con))));
-	} else
-		return (sinphi + sinphi);
+  if (e >= EPSILON) {
+    con = e * sinphi;
+    return (one_es * (sinphi / (1. - con * con) -
+                      (.5 / e) * log((1. - con) / (1. + con))));
+  } else
+    return (sinphi + sinphi);
 }
diff --git a/src/lib/proj4lib/lib/pj_tsfn.cpp b/src/lib/proj4lib/lib/pj_tsfn.cpp
index 987de3aa..acf9c2a3 100644
--- a/src/lib/proj4lib/lib/pj_tsfn.cpp
+++ b/src/lib/proj4lib/lib/pj_tsfn.cpp
@@ -1,11 +1,12 @@
 /* determine small t */
 #ifndef lint
-//static const char SCCSID[]="@(#)pj_tsfn.c	4.3	93/06/12	GIE	REL";
+// static const char SCCSID[]="@(#)pj_tsfn.c	4.3	93/06/12	GIE
+// REL";
 #endif
+#define _USE_MATH_DEFINES
 #include <math.h>
-	long double
-pj_tsfn(long double phi, long double sinphi, long double e) {
-	sinphi *= e;
-	return (tan (.5 * (M_PI_2 - phi)) /
-	   pow((1. - sinphi) / (1. + sinphi), .5 * e));
+long double pj_tsfn(long double phi, long double sinphi, long double e) {
+  sinphi *= e;
+  return (tan(.5 * (M_PI_2 - phi)) /
+          pow((1. - sinphi) / (1. + sinphi), .5 * e));
 }