Strip screen number from DISPLAY when locating X11 socket (#364)

* Strip screen number from DISPLAY when locating X11 socket

DISPLAY values like :0.0 produced socket path X0.0, but the socket is
named X0. Window manager detection failed with 'Can't run Zwift without
window manager'. Strip the screen-number suffix before the check.

Fixes #363

* Strip screen number from DISPLAY in build-image.sh X11 check

Author: netbrain

src/build-image.sh

@@ -127,7 +127,11 @@ fi
 
 # Configure window manager
 msgbox info "Using X11 window manager"
-if [[ -z ${DISPLAY} ]] || [[ ! -S /tmp/.X11-unix/X${DISPLAY#*:} ]]; then
+# DISPLAY is [host]:displaynumber[.screennumber] but the X11 socket is named
+# by the display number alone, so strip the host prefix and screen suffix.
+x11_display="${DISPLAY#*:}"
+x11_display="${x11_display%.*}"
+if [[ -z ${DISPLAY} ]] || [[ ! -S /tmp/.X11-unix/X${x11_display} ]]; then
     msgbox error "X11 is not running!"
     exit 1
 fi

src/zwift.sh

@@ -591,9 +591,13 @@ if [[ ${WINE_EXPERIMENTAL_WAYLAND} -eq 1 ]]; then
     fi
 fi
 if [[ -z ${window_manager} ]]; then
+    # DISPLAY is [host]:displaynumber[.screennumber] but the X11 socket is named
+    # by the display number alone, so strip the host prefix and screen suffix.
+    x11_display="${DISPLAY#*:}"
+    x11_display="${x11_display%.*}"
     if [[ -n ${WAYLAND_DISPLAY} ]]; then
         window_manager="XWayland"
-    elif [[ -n ${DISPLAY} ]] && [[ -S /tmp/.X11-unix/X${DISPLAY#*:} ]]; then
+    elif [[ -n ${DISPLAY} ]] && [[ -S /tmp/.X11-unix/X${x11_display} ]]; then
         window_manager="XOrg"
     else # no window manager, tty?
         msgbox error "Can't run Zwift without window manager"