PointCloudLibrary/pcl — pull request #182 by mmunaro (2013-07-09 16:48:39+00:00)
Title: Added #define _USE_MATH_DEFINES in hog.h for using M_PI in Windows.

mamoto, who uses Windows, told me to add #define _USE_MATH_DEFINES to hog.h.
I checked online and it should be needed for defining M_PI with Visual C++, thus I added it.
In Linux everything remains ok by adding this line.