sed: invalid option -- 'E'

On Sailfish SDK, I get an invalid usage error for sed (GNU sed version 4.1.5) when trying to build mapbox-gl-native.

Based on http://blog.dmitryleskov.com/small-hacks/mysterious-gnu-sed-option-e/ it looks like -r is equivalent to -E

Possible fix for /mapbox/mason/mason.sh:

if test | sed -E 's///g' 2>/dev/null; then
  SED_REGEX_ARG="E"
else
  SED_REGEX_ARG="r"
fi

...

 MASON_CONFIG_INCLUDE_DIRS=$(echo -n "${MASON_CONFIG_CFLAGS}" | sed -$SED_REGEX_ARG -n 's/^-(I|isystem) *([^ ]+)/\2/p' | uniq)
 MASON_CONFIG_DEFINITIONS=$(echo -n "${MASON_CONFIG_CFLAGS}" | sed -$SED_REGEX_ARG -n 's/^-(D) *([^ ]+)/\2/p')
 MASON_CONFIG_OPTIONS=$(echo -n "${MASON_CONFIG_CFLAGS}" | sed -$SED_REGEX_ARG -n '/^-(D|I|isystem) *([^ ]+)/!p')

Start in /mapbox/mason/mason.sh and reproduce the sed -E check on the Sailfish SDK, comparing it with sed -r. Trace the three MASON_CONFIG parsing commands, then verify that the build succeeds and the include directories, definitions, and options are still extracted correctly.