Stub out some glibc-specific functions

This allows support for alternative libcs like musl

diff --git a/base/platform/linux/base_info_linux.cpp b/base/platform/linux/base_info_linux.cpp
index 714d8dc..b70cc23 100644
--- a/base/platform/linux/base_info_linux.cpp
+++ b/base/platform/linux/base_info_linux.cpp
@@ -22,7 +22,7 @@

 #include <sys/utsname.h>

-#ifdef Q_OS_LINUX
+#if defined(Q_OS_LINUX) && defined(__GLIBC__)
 #include <gnu/libc-version.h>
 #endif // Q_OS_LINUX

@@ -200,7 +200,7 @@ QString AutoUpdateKey() {
 }

 QString GetLibcName() {
-#ifdef Q_OS_LINUX
+#if defined(Q_OS_LINUX) && defined(__GLIBC__)
 	return "glibc";
 #endif // Q_OS_LINUX

@@ -208,7 +208,7 @@ QString GetLibcName() {
 }

 QString GetLibcVersion() {
-#ifdef Q_OS_LINUX
+#if defined(Q_OS_LINUX) && defined(__GLIBC__)
 	static const auto result = [&] {
 		const auto version = QString::fromLatin1(gnu_get_libc_version());
 		return QVersionNumber::fromString(version).isNull() ? QString() : version;