sci-mathematics/reduce fatal error: ft2build.h: No such file or directory

[Alessandro-Barbieri]

Makefile:3636: TRACE: fontdemo-fontdemo.o :: /var/tmp/portage/sci-mathematics/reduce-20141130-r2/work/reduce-src-2014-11-30/csl/cslbase/fontdemo.cpp
g++ -DHAVE_CONFIG_H -I. -I/var/tmp/portage/sci-mathematics/reduce-20141130-r2/work/reduce-src-2014-11-30/csl/cslbase  -I "/var/tmp/portage/sci-mathematics/reduce-20141130-r2/work/reduce-src-2014-11-30/cslbuild/x86_64-unknown-gentoo/inclu
de/fox-1.6"   -DBINDIR=/usr/local/bin -DPKGDATADIR=/usr/local/share/reduce -Dfontsdir=reduce.fonts -I../include   -Os -pipe -march=native -mtune=native -fomit-frame-pointer -mfpmath=sse -Wdate-time -Wno-error=implicit-function-declaratio
n -fopenmp -pthread -fno-unroll-all-loops -fno-unroll-loops -fno-peel-loops -Wformat -Wformat-security -Warray-bounds -Wclobbered -Wimplicit-function-declaration -Wvolatile-register-var -ltinfo -Wl,-O1 -Wl,--as-needed -Wl,-fuse-ld=gold -
lpthread -lgomp -Wl,--hash-style=gnu -fno-strict-aliasing -O2 -Wall -MT fontdemo-fontdemo.o -MD -MP -MF .deps/fontdemo-fontdemo.Tpo -c -o fontdemo-fontdemo.o `test -f 'fontdemo.cpp' || echo '/var/tmp/portage/sci-mathematics/reduce-201411
30-r2/work/reduce-src-2014-11-30/csl/cslbase/'`fontdemo.cpp
cc1plus: warning: command line option ‘-Wimplicit-function-declaration’ is valid for C/ObjC but not for C++
In file included from /var/tmp/portage/sci-mathematics/reduce-20141130-r2/work/reduce-src-2014-11-30/csl/cslbase/fontdemo.cpp:94:
/usr/include/X11/Xft/Xft.h:39:10: fatal error: ft2build.h: No such file or directory
   39 | #include <ft2build.h>
      |          ^~~~~~~~~~~~
compilation terminated.
gmake[3]: *** [Makefile:3636: fontdemo-fontdemo.o] Error 1
gmake[2]: *** [Makefile:1108: all] Error 2
gmake[1]: *** [Makefile:618: all] Error 2
Building failed with return code 2 for version cslbuild/x86_64-unknown-gentoo
make: *** [Makefile:11: all] Error 2
 * ERROR: sci-mathematics/reduce-20141130-r2::mv failed (compile phase):
 *   emake failed

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