Linux: Add back the "C99" comment within "loader_platform.h"
Linux: Add back the "C99" comment within "loader_platform.h"

Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,critsec/Vulkan-LoaderAndValidationLayers,sashinde/VulkanTools,KhronosGroup/Vulkan-LoaderAndValidationLayers,sashinde/VulkanTools,sashinde/VulkanTools,elongbug/Vulkan-LoaderAndValidationLayers,Radamanthe/VulkanSamples,KhronosGroup/Vulkan-LoaderAndValidationLayers,critsec/Vulkan-LoaderAndValidationLayers,elongbug/Vulkan-LoaderAndValidationLayers,sashinde/VulkanTools,KhronosGroup/Vulkan-LoaderAndValidationLayers,Radamanthe/VulkanSamples,KhronosGroup/Vulkan-LoaderAndValidationLayers,Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,elongbug/Vulkan-LoaderAndValidationLayers,critsec/Vulkan-LoaderAndValidationLayers,critsec/Vulkan-LoaderAndValidationLayers,elongbug/Vulkan-LoaderAndValidationLayers