gnu: libreoffice: Fix build with newer GLM.

* gnu/packages/patches/libreoffice-glm.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.
* gnu/packages/libreoffice.scm (libreoffice)[source](patches): Add it.

gnu/local.mk

@@ -880,6 +880,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/libmygpo-qt-fix-qt-5.11.patch		\
   %D%/packages/patches/libmygpo-qt-missing-qt5-modules.patch	\
   %D%/packages/patches/libreoffice-icu.patch			\
+  %D%/packages/patches/libreoffice-glm.patch			\
   %D%/packages/patches/libsndfile-armhf-type-checks.patch	\
   %D%/packages/patches/libsndfile-CVE-2017-8361-8363-8365.patch	\
   %D%/packages/patches/libsndfile-CVE-2017-8362.patch		\

gnu/packages/libreoffice.scm

@@ -907,7 +907,8 @@ converting QuarkXPress file format.  It supports versions 3.1 to 4.1.")
       (sha256
        (base32
         "0vnmb231hyhxm7klaqd8vp3rmvix145bq8iqzv19jgl1yaqkxl21"))
-      (patches (search-patches "libreoffice-icu.patch"))))
+      (patches (search-patches "libreoffice-icu.patch"
+                               "libreoffice-glm.patch"))))
     (build-system gnu-build-system)
     (native-inputs
      `(("bison" ,bison)

gnu/packages/patches/libreoffice-glm.patch

@@ -0,0 +1,58 @@
+Fix build with GLM 0.9.9.
+
+This patch is an amalgamation of these upstream commits:
+
+https://github.com/LibreOffice/core/commit/953c4add8fd76d88f49a81ae4c21a1fdcc007e57
+https://github.com/LibreOffice/core/commit/5f1bf6598b5725ad1e50ae9f7ec7524cc8a834fa
+
+diff --git a/chart2/Library_chartcore.mk b/chart2/Library_chartcore.mk
+index 28bc87b89057..69d4c0552636 100644
+--- a/chart2/Library_chartcore.mk
++++ b/chart2/Library_chartcore.mk
+@@ -23,6 +23,12 @@ $(eval $(call gb_Library_add_defs,chartcore,\
+     -DOOO_DLLIMPLEMENTATION_CHARTVIEW \
+ ))
+ 
++ifeq ($(SYSTEM_GLM),TRUE)
++$(eval $(call gb_Library_add_defs,chartcore,\
++        -DGLM_ENABLE_EXPERIMENTAL \
++))
++endif
++
+ $(eval $(call gb_Library_set_precompiled_header,chartcore,$(SRCDIR)/chart2/inc/pch/precompiled_chartcore))
+ 
+ $(eval $(call gb_Library_use_externals,chartcore,\
+diff --git a/vcl/Library_vcl.mk b/vcl/Library_vcl.mk
+index c1f3cc5324e7..0b684c6185a9 100644
+--- a/vcl/Library_vcl.mk
++++ b/vcl/Library_vcl.mk
+@@ -49,6 +49,12 @@ $(eval $(call gb_Library_add_defs,vcl,\
+ 	-DENABLE_MERGELIBS=$(if $(MERGELIBS),1,0) \
+ ))
+ 
++ifeq ($(SYSTEM_GLM),TRUE)
++$(eval $(call gb_Library_add_defs,vcl,\
++        -DGLM_ENABLE_EXPERIMENTAL \
++))
++endif
++
+ $(eval $(call gb_Library_use_sdk_api,vcl))
+ 
+ $(eval $(call gb_Library_use_custom_headers,vcl,\
+diff --git a/vcl/Executable_icontest.mk b/vcl/Executable_icontest.mk
+index ce163303f8a4..8c917b71cd0e 100644
+--- a/vcl/Executable_icontest.mk
++++ b/vcl/Executable_icontest.mk
+@@ -19,6 +19,12 @@ $(eval $(call gb_Executable_use_externals,icontest,\
+ ))
+ endif
+ 
++ifeq ($(SYSTEM_GLM),TRUE)
++$(eval $(call gb_Executable_add_defs,icontest,\
++    -DGLM_ENABLE_EXPERIMENTAL \
++))
++endif
++
+ $(eval $(call gb_Executable_use_api,icontest,\
+     offapi \
+     udkapi \