diff --git a/chromium-browser-stable.spec b/chromium-browser-stable.spec
index 24ec5ec..d67734f 100644
--- a/chromium-browser-stable.spec
+++ b/chromium-browser-stable.spec
@@ -360,13 +360,15 @@ glibc_version="$(rpm -q --queryformat "%{VERSION}" glibc | sed -e 's/\.//g')"
 # glibc 2.27 is used as a stop point, because today (17.10.2018) Chromium
 # is built with system glibc 2.27 in ALT Sisyphus,
 # ROSA has glibc 2.25, and chromium 69 is unbuildable with it
+%define use_custom_libcxx_macro_tmpfile %{buildroot}/use_custom_libcxx.tmp
 if [ "$glibc_version" -lt 227 ]
 	then use_custom_libcxx='true'
 	else use_custom_libcxx='false'
 fi
-export use_custom_libcxx
+echo "$use_custom_libcxx" > %{use_custom_libcxx_macro_tmpfile}
 echo "DEBUG: use_custom_libcxx = ${use_custom_libcxx}"
-%define use_custom_libcxx %(echo ${use_custom_libcxx})
+%define use_custom_libcxx_macro %(cat %{use_custom_libcxx_macro_tmpfile})
+rm -fv %{use_custom_libcxx_macro_tmpfile}
 
 %build
 %define use_gold true
@@ -436,7 +438,7 @@ CXXFLAGS="$CXXFLAGS -Wno-error=attributes -Wno-error=comment -Wno-error=unused-v
 # v NO TABS IN HERE!
 %define gn_config use_sysroot=false \
                   system_libdir="%{_lib}" \
-                  use_custom_libcxx="%{use_custom_libcxx}" \
+                  use_custom_libcxx="%{use_custom_libcxx_macro}" \
                   icu_use_data_file=true \
                   enable_nacl=false \
                   optimize_webui=true \