Merge branch 'FixFFTW3' into 'master'

Fix finding FFTW3 libraries

Closes #53

See merge request !69

CMake/FindFFTW3.cmake

@@ -75,7 +75,7 @@ set(_check_list)
 foreach(_lib ${_libraries})
   string(TOUPPER ${_lib} _LIB)
   find_library(${_LIB}_LIBRARY ${_lib}
-    HINTS ${FFTW3_ROOT_DIR} PATH_SUFFIXES lib)
+    HINTS ${FFTW3_ROOT_DIR} $ENV{FFTW3_ROOT_DIR} PATH_SUFFIXES lib)
   mark_as_advanced(${_LIB}_LIBRARY)
   list(APPEND FFTW3_LIBRARIES ${${_LIB}_LIBRARY})
   list(APPEND _check_list ${_LIB}_LIBRARY)
@@ -83,7 +83,7 @@ endforeach(_lib ${_libraries})
 
 # Search for the header file.
 find_path(FFTW3_INCLUDE_DIR fftw3.h 
-  HINTS ${FFTW3_ROOT_DIR} PATH_SUFFIXES include)
+  HINTS ${FFTW3_ROOT_DIR} $ENV{FFTW3_ROOT_DIR} PATH_SUFFIXES include)
 mark_as_advanced(FFTW3_INCLUDE_DIR)
 list(APPEND _check_list FFTW3_INCLUDE_DIR)
 
@@ -92,4 +92,4 @@ set(FFTW3_INCLUDE_DIRS ${FFTW3_INCLUDE_DIR})
 # Handle the QUIETLY and REQUIRED arguments and set FFTW_FOUND to TRUE if
 # all listed variables are TRUE
 include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(FFTW3 DEFAULT_MSG ${_check_list})
\ No newline at end of file
+find_package_handle_standard_args(FFTW3 DEFAULT_MSG ${_check_list})