LibGfx: Fix sign-compare compile error in TGALoader

I'm not sure why this isn't caught on other people's setups or CI, but
when building on NixOS it fails with:

    error: comparison of integer expressions of different signedness:
    ‘size_t’ {aka ‘long unsigned int’} and ‘int’ [-Werror=sign-compare]

1 files changed, 4 insertions, 2 deletions

diff --git a/Userland/Libraries/LibGfx/TGALoader.cpp b/Userland/Libraries/LibGfx/TGALoader.cpp
index f6928d6985..067299454a 100644
--- a/Userland/Libraries/LibGfx/TGALoader.cpp
+++ b/Userland/Libraries/LibGfx/TGALoader.cpp
@@ -209,7 +209,8 @@ bool TGAImageDecoderPlugin::decode_tga_header()
 
     auto bytes_remaining = reader->data().size() - reader->index();
 
-    if (m_context->header.data_type_code == TGADataType::UncompressedRGB && bytes_remaining < (m_context->header.width * m_context->header.height * (m_context->header.bits_per_pixel / 8)))
+    // FIXME: Check for multiplication overflow!
+    if (m_context->header.data_type_code == TGADataType::UncompressedRGB && bytes_remaining < static_cast<size_t>(m_context->header.width * m_context->header.height * (m_context->header.bits_per_pixel / 8)))
         return false;
 
     if (m_context->header.bits_per_pixel < 8 || m_context->header.bits_per_pixel > 32)
@@ -228,7 +229,8 @@ ErrorOr<bool> TGAImageDecoderPlugin::validate_before_create(ReadonlyBytes data)
     if (data.size() < sizeof(TGAHeader))
         return false;
     TGAHeader const& header = *reinterpret_cast<TGAHeader const*>(data.data());
-    if (header.data_type_code == TGADataType::UncompressedRGB && data.size() < (header.width * header.height * (header.bits_per_pixel / 8)))
+    // FIXME: Check for multiplication overflow!
+    if (header.data_type_code == TGADataType::UncompressedRGB && data.size() < static_cast<size_t>(header.width * header.height * (header.bits_per_pixel / 8)))
         return false;
     if (header.bits_per_pixel < 8 || header.bits_per_pixel > 32)
         return false;