multiple compilations?

[<matti suomedia com>]

I am using Dev C++ 5 and GTK/Win32 (rc-17) and the simplest window will not build/compile  :(

Compiler: Default compiler
Building Makefile: "C:\Dev-Cpp\projects\project1\Makefile.win"
Finding dependencies for file: C:\Dev-Cpp\projects\project1\src\interface.c
Finding dependencies for file: C:\Dev-Cpp\projects\project1\src\main.c
Finding dependencies for file: C:\Dev-Cpp\projects\project1\src\support.c
Finding dependencies for file: C:\Dev-Cpp\projects\project1\src\callbacks.c
Executing  make...
make.exe -f "C:\Dev-Cpp\projects\project1\Makefile.win" all
g++.exe -c src/interface.c -o src/interface.o -I"C:/GTK/INCLUDE"  -I"C:/GTK/INCLUDE/GTK-2.0"  
-I"C:/GTK/INCLUDE/GLIB-2.0"  -I"C:/GTK/INCLUDE/PANGO-1.0"  -I"C:/GTK/INCLUDE/ATK-1.0"  
-I"C:/GTK/INCLUDE/GTKGLEXT-1.0"  -I"C:/GTK/LIB/GTK-2.0/INCLUDE"  -I"C:/GTK/LIB/GLIB-2.0/INCLUDE"  
-I"C:/GTK/LIB/GTKGLEXT-1.0/INCLUDE"  -I"C:/GTK/INCLUDE/LIBGLADE-2.0"  -I"C:/GTK/INCLUDE/LIBXML2"  
-I"C:/Dev-Cpp/include/c++/3.3.1"  -I"C:/Dev-Cpp/include/c++/3.3.1/mingw32"  
-I"C:/Dev-Cpp/include/c++/3.3.1/backward"  -I"C:/Dev-Cpp/lib/gcc-lib/mingw32/3.3.1/include"  
-I"C:/Dev-Cpp/include"  -mms-bitfields `pkg-config gtk+-2.0 --cflags`   -fmessage-length=0

g++.exe: cannot specify -o with -c or -S and multiple compilations

make.exe: *** [src/interface.o] Error 1

Execution terminated

Any help much appreciated!

Matti