boost is not part of the Fedora Flatpak SDK after all

...contrary to what eefb0e3720 "boost is part of
the Fedora, but not of the RHEL Flatpak SDK" had claimed (and which this commit
thus effectively reverts).  In Fedora, boost is part of flatpak-common, but
which is built with an /app, not a /usr prefix.

(And as we no longer append to flatpakoptions anywhere, we can switch back from
%global to %define.)

libreoffice.spec

@@ -1066,10 +1066,7 @@ SMP_MFLAGS=%{?_smp_mflags}
 SMP_MFLAGS=$[${SMP_MFLAGS/-j/}]
 
 %if 0%{?flatpak}
-%global flatpakoptions --with-beanshell-jar=/app/share/java/bsh.jar --with-external-dict-dir=/app/share/myspell --with-external-hyph-dir=/app/share/hyphen --with-external-thes-dir=/app/share/mythes --with-flute-jar=/app/share/java/flute.jar --with-jdk-home=/app/lib/jvm/java --with-jfreereport-jar=/app/share/java/flow-engine.jar --with-libbase-jar=/app/share/java/libbase.jar --with-libfonts-jar=/app/share/java/libfonts.jar --with-libformula-jar=/app/share/java/libformula.jar --with-liblayout-jar=/app/share/java/liblayout.jar --with-libloader-jar=/app/share/java/libloader.jar --with-librepository-jar=/app/share/java/librepository.jar --with-libserializer-jar=/app/share/java/libserializer.jar --with-libxml-jar=/app/share/java/libxml.jar --with-sac-jar=/app/share/java/sac.jar FIREBIRDCONFIG=%{_libdir}/fb_config QT4INC=%{_includedir}
+%define flatpakoptions --with-beanshell-jar=/app/share/java/bsh.jar --with-boost-libdir=%{_libdir} --with-external-dict-dir=/app/share/myspell --with-external-hyph-dir=/app/share/hyphen --with-external-thes-dir=/app/share/mythes --with-flute-jar=/app/share/java/flute.jar --with-jdk-home=/app/lib/jvm/java --with-jfreereport-jar=/app/share/java/flow-engine.jar --with-libbase-jar=/app/share/java/libbase.jar --with-libfonts-jar=/app/share/java/libfonts.jar --with-libformula-jar=/app/share/java/libformula.jar --with-liblayout-jar=/app/share/java/liblayout.jar --with-libloader-jar=/app/share/java/libloader.jar --with-librepository-jar=/app/share/java/librepository.jar --with-libserializer-jar=/app/share/java/libserializer.jar --with-libxml-jar=/app/share/java/libxml.jar --with-sac-jar=/app/share/java/sac.jar FIREBIRDCONFIG=%{_libdir}/fb_config QT4INC=%{_includedir}
-%if 0%{?rhel}
-%global flatpakoptions %{flatpakoptions} --with-boost-libdir=%{_libdir}
-%endif
 %endif
 
 # TODO: enable coinmp?