Never try to limit memory on macOS

We can't limit memory on macOS. Before macOS 12
limitSystemMemoryOnPOSIX() does not actually do anything on macOS.
Anyway, it just succeed, since macOS 12 it returns error and retdec
can't start.

To be honest Apple can control memmory limit via so-called the ledger()
system call which is private. An old verison which was opened to
OpenSource (from 10.9-10.10?) using setrlimit() but at some point
setrlimit() was broken and not ledger(). Probably at macOS 12 the
setrlimit() was completley broken.

Because we haven't got any other choose just return true which haven't
change anything.

See: avast#379
Fixes: avast#1045

src/utils/memory.cpp

@@ -27,7 +27,7 @@ namespace utils {
 
 namespace {
 
-#ifdef OS_POSIX
+#if defined(OS_POSIX) && !defined(OS_MACOS)
 
 /**
 * @brief Implementation of @c limitSystemMemory() on POSIX-compliant systems.
@@ -115,10 +115,21 @@ std::size_t getTotalSystemMemoryOnMacOS() {
 * @brief Implementation of @c limitSystemMemory() on MacOS.
 */
 bool limitSystemMemoryOnMacOS(std::size_t limit) {
-	// Warning: We have found that limitSystemMemoryOnPOSIX() does not actually
-	// do anything on macOS. We need to find another way. See
-	// https://github.com/avast/retdec/issues/379
-	return limitSystemMemoryOnPOSIX(limit);
+	// Warning: We can't limit memory on macOS. Before macOS 12
+	// limitSystemMemoryOnPOSIX() does not actually do anything on macOS.
+	// Anyway, it just succeed, since macOS 12 it returns error and retdec can't
+	// start. See:
+	// - https://github.com/avast/retdec/issues/379
+	// - https://github.com/avast/retdec/issues/1045
+	//
+	// To be honest Apple can control memmory limit via so-called the ledger()
+	// system call which is private. An old verison which was opened to OpenSource
+	// (from 10.9-10.10?) using setrlimit() but at some point setrlimit() was broken
+	// and not ledger(). Probably at macOS 12 the setrlimit() was completley broken.
+	//
+	// Because we haven't got any other choose just return true which haven't
+	// change anything.
+	return true;
 }
 
 #elif defined(OS_BSD)