include libfyaml headers from non-standard locations

the CMake manual promises more than it holds.
Also adding some diagnostics+fixes for zlib, we still assume that it
exists (true on most systems, HDF5 also requires it normally)
see also https://stackoverflow.com/questions/21593

CMakeLists.txt

@@ -32,6 +32,7 @@ set(ENV{PKG_CONFIG_PATH} "$ENV{PETSC_DIR}/$ENV{PETSC_ARCH}/externalpackages:$ENV
 pkg_check_modules(HDF5 hdf5)
 pkg_check_modules(FFTW3 fftw3)
 pkg_check_modules(fYAML libfyaml)
+pkg_check_modules(zlib zlib)
 
 file(STRINGS ${PROJECT_SOURCE_DIR}/VERSION DAMASK_VERSION)
 
@@ -118,10 +119,14 @@ endif()
 set(CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE} "${CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE}} ${PETSC_INCLUDES} ${BUILDCMD_POST}")
 
 set(CMAKE_Fortran_LINK_EXECUTABLE "${CMAKE_Fortran_LINK_EXECUTABLE} <OBJECTS> -o <TARGET> <LINK_LIBRARIES> -L${PETSC_LIBRARY_DIRS} -lpetsc ${PETSC_EXTERNAL_LIB} -lz")
+
 if(fYAML_FOUND STREQUAL "1")
     set(CMAKE_Fortran_LINK_EXECUTABLE "${CMAKE_Fortran_LINK_EXECUTABLE} -L${fYAML_LIBRARY_DIRS} -l${fYAML_LIBRARIES}")
     add_definitions(-DFYAML)
+    pkg_get_variable(fYAML_INCLUDE_DIR libfyaml includedir) # fYAML_INCLUDE_DIRS and fYAML_CFLAGS are not working
+    set(CMAKE_C_FLAGS_${CMAKE_BUILD_TYPE} "${CMAKE_C_FLAGS_${CMAKE_BUILD_TYPE}} -I${fYAML_INCLUDE_DIR}")
 endif()
+
 set(CMAKE_Fortran_LINK_EXECUTABLE "${CMAKE_Fortran_LINK_EXECUTABLE} ${BUILDCMD_POST}")
 
 message("Fortran Compiler Flags:\n${CMAKE_Fortran_FLAGS_${CMAKE_BUILD_TYPE}}\n")

src/C_routines.c

@@ -7,7 +7,7 @@
 #include <pwd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
-#include "zlib.h"
+#include <zlib.h>
 
 #ifdef FYAML
 #include <libfyaml.h>