OSX/CI: step fails to build on branch frameworks

[Marko Käning]

Hi,

step doesn’t locate GSL properly on OSX/CI:
---
In file included from /Users/marko/WC/KDECI-builds/kf5-qt5/step/step/worldfactory.cc:32:
/Users/marko/WC/KDECI-builds/kf5-qt5/step/stepcore/gslsolver.h:32:10: fatal error: 'gsl/gsl_odeiv.h' file not found
#include <gsl/gsl_odeiv.h>
         ^
---

GSL is installed via MacPorts (contents' output shortened):
---
$ port contents gsl
Port gsl contains:
  /opt/local/bin/gsl-config
  ...
  /opt/local/include/gsl/gsl_blas.h
  ...
  /opt/local/lib/libgsl.0.dylib
  ...
  /opt/local/lib/pkgconfig/gsl.pc
  /opt/local/share/aclocal/gsl.m4
  /opt/local/share/info/gsl-ref.info
  ...
  /opt/local/share/man/man1/gsl-config.1.gz
  ...
---
with gsl.pc like this:
---
$ cat /opt/local/lib/pkgconfig/gsl.pc
prefix=/opt/local
exec_prefix=/opt/local
libdir=/opt/local/lib
includedir=/opt/local/include
GSL_CBLAS_LIB=-lgslcblas

Name: GSL
Description: GNU Scientific Library
Version: 1.16
Libs: -L/opt/local/lib -lgsl ${GSL_CBLAS_LIB}  -lm 
Cflags: -I/opt/local/include
---

How can the build system be fixed accordingly?

Greets,
Marko