Fix issues building on some Linux systems

- include sys/types.h and strings for DKRgzip
- link with pthread for std::thread on some systems

tools/Makefile

@@ -42,7 +42,7 @@ $(BUILD_DIR)/%.o: %.cpp
 	$(CXX) -c $< -o $@ $(CXXFLAGS)
 
 dkr_assets_tool: $(dkr_assets_tool_OBJ_FILES)
-	$(CXX) $^ -o $@ $(CXXFLAGS) $(LDFLAGS)
+	$(CXX) $^ -o $@ $(CXXFLAGS) $(LDFLAGS) -lpthread
 
 .PHONY: all clean distclean default
 

tools/dkr_assets_tool_classes/libs/DKRGzip.c

@@ -1,6 +1,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
+#include <sys/types.h>
 #include "DKRGzip.h"
 
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