Fix missing Pango support in R 3.x for openSUSE 15.6

On R <= 3.6, running png() or similar was returning an error, and
getOption("bitmapType") returned "Xlib" instead of "cairo" as expected.

builder/Dockerfile.opensuse-156

@@ -99,6 +99,9 @@ ENV CONFIGURE_OPTIONS="\
 # https://solutions.posit.co/envs-pkgs/using-rjava/
 ENV JAVA_HOME=/usr/lib64/jvm/jre-11-openjdk
 
+# R 3.x requires PCRE2 for Pango support on SUSE 15.6
+ENV INCLUDE_PCRE2_IN_R_3 yes
+
 COPY package.opensuse-156 /package.sh
 COPY build.sh .
 COPY patches /patches

builder/build.sh

@@ -118,7 +118,7 @@ compile_r() {
   #
   # The INCLUDE_PCRE2_IN_R_3 environment variable can be set to include PCRE2
   # in R 3.x builds, for distributions where PCRE2 is always required.
-  # In Debian 11/Ubuntu 22/RHEL 9, Pango now depends on PCRE2, so R 3.x will not be compiled with
+  # In Debian 11/Ubuntu 22/RHEL 9/SUSE 15.6, Pango now depends on PCRE2, so R 3.x will not be compiled with
   # Pango support if the PCRE2 pkg-config file is missing.
   if [[ "${r_version}" =~ ^3 ]] && pkg-config --exists libpcre2-8 && [ -z "$INCLUDE_PCRE2_IN_R_3" ]; then
     mkdir -p /tmp/pcre2