cross-compiled fontconfig is broken

[rofl0r]

there are a lot of warnings like

fcfreetype.c:71:2: warning: #warning "No FT_Get_BDF_Property: Please install freetype 2.1.4 or later" [-Wcpp]                       
 #warning "No FT_Get_BDF_Property: Please install freetype 2.1.4 or later"                                                          
  ^~~~~~~                                                                                                                           
fcfreetype.c:75:2: warning: #warning "No FT_Get_PS_Font_Info: Please install freetype 2.1.1 or later" [-Wcpp]                       
 #warning "No FT_Get_PS_Font_Info: Please install freetype 2.1.1 or later"                                                          
  ^~~~~~~                                                                                                                           
mv -f .deps/fccache.Tpo .deps/fccache.Plo                                                                                           
/bin/bash ../libtool  --tag=CC   --mode=compile armv7l-linux-musleabi-gcc -L/home/rofl/x-prefix/arm/lib -isystem /home/rofl/x-prefi$
fcfreetype.c:1999:2: warning: #warning "No FT_Get_Next_Char: Please install freetype version 2.1.0 or newer" [-Wcpp]                
 #warning "No FT_Get_Next_Char: Please install freetype version 2.1.0 or newer"                                                     
  ^~~~~~~                                                                                                                           

in the log which arent there on a native build.
the result is a broken fontconfig which causes endless loops in all applications trying to use ttf fonts (happen with fc-cache and st, both looping between 2 positions in dejavu-sans-bold.ttf).