qt bbappends: play nice with bbappends in other layers by incrementing PRINC instead of overwriting it

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>

meta-oe/recipes-qt/qt4/qt4-embedded_4.7.4.bbappend

@@ -3,3 +3,4 @@ QT_SQL_DRIVER_FLAGS = "-no-sql-ibase -plugin-sql-mysql -no-sql-odbc -plugin-sql-
 QT_CONFIG_FLAGS += "-I${STAGING_INCDIR}/mysql \
                     -I${STAGING_INCDIR}/postgresql"
 
+PRINC := "${@int(PRINC) + 1}"

meta-oe/recipes-qt/qt4/qt4-embedded_4.8.0.bbappend

@@ -3,4 +3,4 @@ QT_SQL_DRIVER_FLAGS = "-no-sql-ibase -plugin-sql-mysql -no-sql-odbc -plugin-sql-
 QT_CONFIG_FLAGS += "-I${STAGING_INCDIR}/mysql \
                     -I${STAGING_INCDIR}/postgresql"
 
-PRINC = "1"
+PRINC := "${@int(PRINC) + 1}"

meta-oe/recipes-qt/qt4/qt4-x11-free_4.7.4.bbappend

@@ -3,3 +3,4 @@ QT_SQL_DRIVER_FLAGS = "-no-sql-ibase -plugin-sql-mysql -no-sql-odbc -plugin-sql-
 QT_CONFIG_FLAGS += "-I${STAGING_INCDIR}/mysql \
                     -I${STAGING_INCDIR}/postgresql"
 
+PRINC := "${@int(PRINC) + 1}"

meta-oe/recipes-qt/qt4/qt4-x11-free_4.8.0.bbappend

@@ -3,4 +3,4 @@ QT_SQL_DRIVER_FLAGS = "-no-sql-ibase -plugin-sql-mysql -no-sql-odbc -plugin-sql-
 QT_CONFIG_FLAGS += "-I${STAGING_INCDIR}/mysql \
                     -I${STAGING_INCDIR}/postgresql"
 
-PRINC = "1"
+PRINC := "${@int(PRINC) + 1}"