Change math constants, similar to PR #372. Use M_ namespace with the de facto standard M_PI and its ilk. Change names that are widely used in the project to be in the M_ namespace, so HALFPI becomes M_HALFPI. HALFPI is #defined as M_PI_2 (the defacto standard name). #defines _USE_MATH_DEFINES for MS Visual Studio (I didn't personally test this part, but Appveyor will not build otherwise).

1 files changed, 2 insertions, 2 deletions

diff --git a/src/geod.c b/src/geod.c
index c429c513..12513cb0 100644
--- a/src/geod.c
+++ b/src/geod.c
@@ -87,8 +87,8 @@ process(FILE *fid) {
 		}
 		if (!*s && (s > line)) --s; /* assumed we gobbled \n */
 		if (pos_azi) {
-			if (al12 < 0.) al12 += TWOPI;
-			if (al21 < 0.) al21 += TWOPI;
+			if (al12 < 0.) al12 += M_TWOPI;
+			if (al21 < 0.) al21 += M_TWOPI;
 		}
 		if (fullout) {
 			printLL(phi1, lam1); TAB;