problems building on Ubuntu 18.04

[Michal Szymanski]

On Ubuntu 18.04, with tcl-dev package installed, there are following problems:

1. "configure" fails to find tclConfig.sh
checking for tclConfig.sh... configure: error: I could not find tclConfig.sh in /usr/share/tcltk/tcl8.6

actually, the file is in /usr/lib/tcltk/tcl8.6, also linked to /usr/lib

2. After giving the path explicitely:

configure --with-tclconfig=/usr/lib succeeds but then 'make' fails unable to find "tcl.h"
That's really strange as sourcing tclConfig.sh file sets the environment variable
TCL_INCLUDE_SPEC='-I/usr/include/tcl8.6'

Only after giving extra flag to configure:
CXXFLAGS=-I/usr/include/tcl8.6

ical gets built properly

[Johann Schoonees (johann-m)]

I can confirm that this also affects Xubuntu 18.04 with tcl/tk 8.5. This ran apparently successfully:

./configure --prefix=/home/me --with-tclconfig=/usr/lib/tcl8.5 --with-tkconfig=/usr/lib/tk8.5 CPPFLAGS=-I/usr/include/tcl8.5

However, the subsequent make fails:

main.C: In function ‘int Ical_Init(Tcl_Interp*)’:
main.C:147:65: error: invalid conversion from ‘unsigned char*’ to ‘const char*’ [-fpermissive]
 (Tk_DefineBitmap(tcl,Tk_GetUid(id),n##_bits,n##_width,n##_height) == TCL_OK)
                                                                 ^
main.C:154:14: note: in expansion of macro ‘MAKE_BITMAP’
         if (!MAKE_BITMAP(tcl, "left_arrow", left)) return TCL_ERROR;
              ^~~~~~~~~~~
In file included from /usr/include/tcl8.5/tk.h:1537:0,
                 from main.C:24:
...

[Johann Schoonees (johann-m)]

Configured, built and installed successfully on Xubuntu 16.04 and Xubuntu 18.04 after installing tcl/tk8.6, but still needed explicit addition of -I/usr/include/tcl8.6 :

sudo apt-get install tcl8.6-dev tk8.6-dev

./configure --prefix=/home/me --with-tclconfig=/usr/lib/tcl8.6 --with-tkconfig=/usr/lib/tk8.6 CPPFLAGS=-I/usr/include/tcl8.6
make
make install