Enable more sanitizers in make develop (#1588)

- `-fsanitize=undefined` encompasses multiple checks we were specifying

- "detect_leaks=1" for `__asan_default_options` checks for memory leaks
  (except for with macOS clang++, which does not support LSan)

- `-fsanitize=float-divide-by-zero` is an extra UBSan check
  (and reveals a UB bug to fix with fixed-point `DIV` and `LOG`)

src/version.cpp

@@ -6,6 +6,21 @@
 
 #include "helpers.hpp"
 
+// We do not build `make develop` with `-fsanitize=leak` because macOS clang++ does not support it.
+// Instead, we enable ASan (`-fsanitize=address`) to check for memory leaks in all four programs.
+#ifdef __clang__
+	#if __has_feature(address_sanitizer) && !defined(__SANITIZE_ADDRESS__)
+		#define __SANITIZE_ADDRESS__
+	#endif
+#endif
+#if defined(__SANITIZE_ADDRESS__) && !defined(__APPLE__)
+extern "C" {
+	char const *__asan_default_options(void) {
+		return "detect_leaks=1";
+	}
+}
+#endif
+
 // This variable is passed via `-D` from the Makefile, but not from CMake
 // (in which `configure_file()` is used on this file to replace some syntax)
 #ifndef BUILD_VERSION_STRING