GVim compiled from source does not use gtk2

I have two HP-UX machines say A and B with HP-UX 11.11 and 11.31 respectively. I have compiled gvim 7.3 from source an B, and gvim 7.0 on A. On A, gvim uses "version with GTK GUI", Compilation with gcc (...) -DFEAT_GUI_GTK and all works fine. On B, gvim looks different and uses "version with X11-Motif GUI". Here ssh -X does not copy paste on selection exactly as in the thread "GVim compiled from source opened via SSH -X does not copy paste on selection": - copy/paste via select works on a GVim window on A, but not on B. - When I select some text in the GVim window, I can paste it via right-click within that window, but I cannot paste it into anything running locally. When I select something locally, I can paste it locally but when I paste into the GVim window, it pastes the last thing selected in the GVim window, not the last thing selected locally. The Problem is: I cannot rebuild gvim with gtk. Although I have installed GTK+ on the machine via HP depot (GTK 2.6) and using gtk+ is called default in the Makefile configure ends up with compiler option "gcc (...) -DFEAT_GUI_MOTIF". to be more specific: configure gives: checking --enable-gui argument... yes/auto - automatic GUI support checking whether or not to look for GTK+ 2... yes but doesn't search for gtk Libraries. It only looks for Motif: checking for location of Motif GUI libs... /usr/lib/Motif1.1 It doesn't tell me that it is missing anything I can provide! In the directory "auto" the file configure.log shows no failure in searching for GTk, it just doesn't look for! configure:7577: result: yes/auto - automatic GUI support configure:7609: checking whether or not to look for GTK+ 2 configure:7618: result: yes configure:7627: checking whether or not to look for GNOME configure:7636: result: no configure:7644: checking whether or not to look for Motif configure:7653: result: yes configure:7661: checking whether or not to look for Athena configure:7670: result: yes configure:7678: checking whether or not to look for neXtaw configure:7687: result: yes configure:7695: checking whether or not to look for Carbon configure:7704: result: yes configure:7752: checking --disable-gtktest argument configure:7762: result: gtk test enabled configure:7772: checking for pkg-config configure:7803: result: no configure:8035: checking for location of Motif GUI includes configure:8047: result: in default path configure:8062: checking --with-motif-lib argument configure:8076: result: no configure:8081: checking for location of Motif GUI libs configure:8099: result: /usr/lib/Motif1.1 configure:8202: checking for XShapeQueryExtension in -lXext And make starts with OPTION Motif: avalenti@ncc1n:/usr/local/src/vim/vim73/src >make | tee make-minimal.results mkdir objects CC="gcc -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_MOTIF -I/usr/local/include " srcdir=. sh ./osdef.sh gcc -c -I. -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_MOTIF -I/usr/local/include -g -O2 -D_FORTIFY_SOURCE=1 -o objects/buffer.o buffer.c (...) If I force usings gtk with configure --enable-gui=gtk2 make ends up with no error but gvim says: "E25: GUI cannot be used: Not enabled at compile time" How can I force gvim to compile using gtk2?