Darwin build improvements (#406)

---------

Co-authored-by: Ranieri Althoff <[email protected]>

binding.gyp

@@ -19,12 +19,19 @@
     "configurations": {
       "Release": {
         "target_conditions": [
-          ["OS != 'win'", {
+          ["OS not in 'ios mac'", {
+            # Avoid defining _FORTIFY_SOURCE on Darwin
+            "defines+": ["_FORTIFY_SOURCE=2"]
+          }],
+          ["OS not in 'win ios mac'", {
+            # On Darwin with Xcode CLT/LLVM, "-fvisibility=hidden" hide all symbols that
+            # not explicitly marked with __attribute__((visibility("default")))
+            # Flags for sections are specific to ELF binaries
             "cflags+": ["-fdata-sections", "-ffunction-sections", "-fvisibility=hidden"],
             "ldflags+": ["-Wl,--gc-sections"]
           }]
         ],
-        "defines+": ["_FORTIFY_SOURCE=2", "NDEBUG"]
+        "defines+": ["NDEBUG"]
       }
     }
   },
@@ -58,7 +65,7 @@
       "sources": [
         "argon2.cpp"
       ],
-      "cflags_cc+": ["-Wall", "-Wextra", "-Wformat", "-Wnon-virtual-dtor", "-pedantic", "-Werror"],
+      "cflags_cc+": ["-Wall", "-Wextra", "-Wformat", "-Wnon-virtual-dtor", "-pedantic", "-Werror", "-fexceptions"],
       "cflags_cc!": ["-fno-exceptions"],
       "include_dirs": ["<!(node -p \"require('node-addon-api').include_dir\")"],
       "dependencies": ["libargon2"],