sqlcipher: fix passing CFLAGS/LDFLAGS to configure

SQLCIPHER_CONF_ENV is a string used to pass environment variables to the
confgiure script, '+=' operator doesn't have any special meaning inside
it, so CFLAGS+=... is passed to shell, overwriting previous CFLAGS
value. Replace CFLAGS+="..." with CFLAGS="$(TARGET_CFLAGS) ...".

Fixes:
  http://autobuild.buildroot.net/results/dbf/dbf947ad6442fa8e57201ffcc96871361bf39ad7/

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Reviewed-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/sqlcipher/sqlcipher.mk

@@ -10,8 +10,8 @@ SQLCIPHER_DEPENDENCIES = openssl host-tcl
 SQLCIPHER_INSTALL_STAGING = YES
 
 SQLCIPHER_CONF_ENV = \
-	CFLAGS+=" $(SQLCIPHER_CFLAGS)" \
-	LDFLAGS+=" $(SQLCIPHER_LDFLAGS)" \
+	CFLAGS="$(TARGET_CFLAGS) $(SQLCIPHER_CFLAGS)" \
+	LDFLAGS="$(TARGET_LDFLAGS) $(SQLCIPHER_LDFLAGS)" \
 	TCLSH_CMD=$(HOST_DIR)/usr/bin/tclsh$(TCL_VERSION_MAJOR)
 
 SQLCIPHER_CONF_OPT = \