load fftw library on macos if conda or homebrew used

modules/fftw/src/cpp/FFTWWrapper.cpp

@@ -11,6 +11,7 @@
 #if WITH_OPENMP
 #include <omp.h>
 #endif
+#include <cstdlib>
 #include "FFTWDynamicLibrary.hpp"
 #include "FFTWWrapper.hpp"
 #include "DynamicLibrary.hpp"
@@ -192,6 +193,34 @@ freeFFTWLibrary()
     return false;
 }
 //=============================================================================
+#if defined(__APPLE__)
+static bool
+loadFFTWLibraryOnMacOs()
+{
+    bool res = false;
+    char const* CONDA_PREFIX_char = std::getenv("CONDA_PREFIX");
+    if (CONDA_PREFIX_char) {
+        std::string CONDA_LIB = std::string(CONDA_PREFIX_char) + "/lib/";
+        std::string fftwLibraryName = CONDA_LIB + "libfftw3.3" + get_dynamic_library_extension();
+        std::string fftwfLibraryName = CONDA_LIB + "libfftw3f" + get_dynamic_library_extension();
+        res = loadFFTWLibrary(utf8_to_wstring(fftwLibraryName), utf8_to_wstring(fftwfLibraryName));
+    }
+    if (!res) {
+        char const* HOMEBREW_PREFIX_char = std::getenv("HOMEBREW_PREFIX");
+        if (HOMEBREW_PREFIX_char) {
+            std::string HOMEBREW_LIB = std::string(HOMEBREW_PREFIX_char) + "/lib/";
+            std::string fftwLibraryName
+                = HOMEBREW_LIB + "libfftw3.3" + get_dynamic_library_extension();
+            std::string fftwfLibraryName
+                = HOMEBREW_LIB + "libfftw3f" + get_dynamic_library_extension();
+            res = loadFFTWLibrary(
+                utf8_to_wstring(fftwLibraryName), utf8_to_wstring(fftwfLibraryName));
+        }
+    }
+    return res;
+}
+#endif
+//=============================================================================
 bool
 loadFFTWLibrary()
 {
@@ -213,12 +242,15 @@ loadFFTWLibrary()
         res = loadFFTWLibrary(utf8_to_wstring(fftwLibraryName), utf8_to_wstring(fftwfLibraryName));
     }
     if (!res) {
-        // try with version 3.3 macos specific
         std::string fftwLibraryName = "libfftw3.3" + get_dynamic_library_extension();
-        std::string fftwfLibraryName = "libfftw3f" + get_dynamic_library_extension() + ".3";
+        std::string fftwfLibraryName = "libfftw3f" + get_dynamic_library_extension();
         res = loadFFTWLibrary(utf8_to_wstring(fftwLibraryName), utf8_to_wstring(fftwfLibraryName));
     }
-
+#if defined(__APPLE__)
+    if (!res) {
+        res = loadFFTWLibraryOnMacOs();
+    }
+#endif
 #endif
     if (res) {
 #if WITH_OPENMP