build with libunwind where available

gimp.spec

@@ -30,6 +30,12 @@
 %bcond_without hardcoded_python
 # webp support
 %bcond_without webp
+# libunwind support (only available on some architectures)
+%ifarch %{arm} aarch64 hppa ia64 mips ppc %{power64} %{ix86} x86_64
+%bcond_without libunwind
+%else
+%bconf_with libunwind
+%endif
 
 # If Python plug-ins need to be byte-compiled separately
 %if ! 0%{?fedora}%{?rhel} || 0%{?fedora} > 28 || 0%{?rhel} > 7
@@ -136,7 +142,9 @@ BuildRequires:  libmng-devel
 BuildRequires:  libpng-devel >= 1.6.25
 BuildRequires:  librsvg2-devel >= 2.40.6
 BuildRequires:  libtiff-devel
+%if %{with libunwind}
 BuildRequires:  libunwind-devel >= 1.1.0
+%endif
 %if %{with webp}
 BuildRequires:  libwebp-devel >= 0.6.0
 %endif
@@ -179,7 +187,9 @@ Requires:       freetype >= 2.1.7
 Requires:       glib2 >= 2.54.0
 Requires:       gtk2 >= 2.24.10
 Requires:       hicolor-icon-theme
+%if %{with libunwind}
 Requires:       libunwind%{?_isa} >= 1.1.0
+%endif
 Recommends:     mypaint-brushes
 Requires:       pango >= 1.29.4
 Requires:       pygtk2 >= 2.10.4
@@ -680,6 +690,7 @@ make check %{?_smp_mflags}
 %changelog
 * Sat Nov 10 2018 Nils Philippsen <nils@tiptoe.de> - 2:2.10.8-1
 - version 2.10.8
+- build with libunwind where available
 
 * Fri Aug 24 2018 Nils Philippsen <nils@tiptoe.de> - 2:2.10.6-2
 - own all plug-in directories