Drop bundled FindBLAS.cmake that doesn't know about FlexiBLAS

In the end, this doesn't seem to have any effect, but at least the previous
version was detecting openblas.so, which is certaily wrong. IIUC, blas is
only used in combination for some optional features which are disabled ATM.

[skip changelog]

(cherry picked from commit 211e11e642)

dolfin.spec

@@ -29,6 +29,7 @@ ExcludeArch:    %{ix86}
 BuildRequires:  gcc-c++
 BuildRequires:  gnupg2
 BuildRequires:  cmake
+BuildRequires:  pkgconf
 BuildRequires:  boost-devel
 BuildRequires:  eigen3-devel
 BuildRequires:  petsc-devel
@@ -66,6 +67,9 @@ FEniCS Problem Solving Environment.}
 %package devel
 Summary:        Development files for %{name}
 Requires:       %{name} = %{version}-%{release}%{?isa}
+# dolfin headers include headers from other projects
+Requires:       boost-devel
+Requires:       eigen3-devel
 
 %description devel
 %{summary}.
@@ -93,6 +97,9 @@ BuildArch:      noarch
 # Let's just specify an exact version of a dependency, yay!
 sed -i -r 's|pybind11==|pybind11>=|' python/setup.py
 
+# Drop obsolete bundled crap that doesn't support FlexiBLAS
+rm cmake/modules/FindBLAS.cmake
+
 cat >>python/CMakeLists.txt <<EOF
 set(CMAKE_CXX_FLAGS "\${CMAKE_CXX_FLAGS} -I$PWD")
 EOF
@@ -111,9 +118,19 @@ sed -r -i 's|boost/detail/endian.hpp|boost/endian/arithmetic.hpp|' \
 mkdir -p build && cd build
 CFLAGS="%{optflags} -Wno-unused-variable -DH5_USE_110_API" CXXFLAGS="%{optflags} -DH5_USE_110_API" %cmake .. \
   %{cmake_blas_flags} \
-  -DCMAKE_INSTALL_RPATH_USE_LINK_PATH=off
+  -DCMAKE_INSTALL_RPATH_USE_LINK_PATH=off \
+  -Wno-dev
 %make_build
 
+# The flags defined in the pkg-config file are used at runtime.
+# For some reason, the contents are not injected properly.
+# https://fenicsproject.discourse.group/t/cant-define-expression-through-c-returns-fatal-error-ufc-h-no-such-file-or-directory/5472/19
+# https://bugzilla.redhat.com/show_bug.cgi?id=2118536
+ffc_path="$(python3 -c 'import ffc; print(ffc.get_include_path())')"
+eigen_options="$(pkgconf --cflags eigen3)"
+sed -r -i "s|Cflags:.*|\\0 -I${ffc_path} ${eigen_options}|" \
+    dolfin.pc
+
 # "temporary install" so the python build can find the stuff it needs
 %make_install
 
@@ -128,9 +145,9 @@ cd ../python
 VERBOSE=1 CMAKE_PREFIX_PATH=%{buildroot}/usr/share/dolfin/cmake CMAKE_SKIP_INSTALL_RPATH=yes CMAKE_SKIP_RPATH=yes %py3_install
 
 sed -r -i '1 {s|#!/usr/bin/env python.*|#!%{__python3}|}' \
-    %{buildroot}/usr/bin/dolfin-order \
-    %{buildroot}/usr/bin/dolfin-plot \
-    %{buildroot}/usr/bin/dolfin-convert
+    %{buildroot}%{_bindir}/dolfin-order \
+    %{buildroot}%{_bindir}/dolfin-plot \
+    %{buildroot}%{_bindir}/dolfin-convert
 
 # this file is just pointless
 rm %{buildroot}/usr/share/dolfin/dolfin.conf
@@ -145,8 +162,8 @@ ctest -V %{?_smp_mflags}
 %files
 %license COPYING COPYING.LESSER AUTHORS
 %doc README.rst
-/usr/bin/dolfin-version
-/usr/bin/fenics-version
+%{_bindir}/dolfin-version
+%{_bindir}/fenics-version
 %{_libdir}/libdolfin.so.%{fenics_version}
 %{_libdir}/libdolfin.so.%{fenics_version}.*
 %dir /usr/share/dolfin
@@ -161,13 +178,13 @@ ctest -V %{?_smp_mflags}
 /usr/share/dolfin/cmake/
 
 %files doc
-/usr/bin/dolfin-get-demos
+%{_bindir}/dolfin-get-demos
 /usr/share/dolfin/demo/
 
 %files -n python3-dolfin
-/usr/bin/dolfin-convert
-/usr/bin/dolfin-order
-/usr/bin/dolfin-plot
+%{_bindir}/dolfin-convert
+%{_bindir}/dolfin-order
+%{_bindir}/dolfin-plot
 %{python3_sitearch}/dolfin/
 %{python3_sitearch}/dolfin_utils/
 %{python3_sitearch}/fenics/