Make C extension non-optional for RPM, .deb builds

Patch setup.py during build of .rpm or .deb
packages to make the C extension non-optional
once again. This should fail the package build
if building the extension fails.

Author: benmwebb

util/debian/patches/ihm-force-c-ext.patch

@@ -0,0 +1,13 @@
+diff --git a/setup.py b/setup.py
+index 6e96b27..c149947 100755
+--- a/setup.py
++++ b/setup.py
+@@ -27,7 +27,7 @@ mod = [Extension("ihm._format",
+                  extra_compile_args=cargs,
+                  swig_opts=['-keyword', '-nodefaultctor',
+                             '-nodefaultdtor', '-noproxy'],
+-                 optional=True)]
++                 optional=False)]
+ 
+ with open("README.md", "r") as fh:
+     long_description = fh.read()

util/debian/patches/series

@@ -0,0 +1 @@
+ihm-force-c-ext.patch

util/python-ihm.spec

@@ -7,6 +7,7 @@ Summary:       Package for handling IHM mmCIF and BinaryCIF files
 Packager:      Ben Webb <ben@salilab.org>
 URL:           https://pypi.python.org/pypi/ihm
 Source:        ihm-%{version}.tar.gz
+Patch0:        ihm-force-c-ext.patch
 BuildRequires: python3-devel, python3-setuptools, gcc
 %if 0%{?rhel} != 7
 BuildRequires: python3-msgpack
@@ -25,6 +26,7 @@ with Python 3.6 or later.
 
 %prep
 %setup -n ihm-%{version}
+%patch -P 0 -p1
 %if 0%{?rhel} == 7
 sed -i -e "s/install_requires=\['msgpack'\]/#/" setup.py
 %endif