test/: Use correct calcurse binary and data dir

We really don't want to use the calcurse(1) binary from "$PATH" here.
Introduce an environment variable "$CALCURSE" which can be used specify
the binary to use and set this variable to the binary located in the
build directory by default. Similarly, add another environment variable
"$DATA_DIR" that can be used to specify a data directory.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

test/Makefile.am

@@ -17,6 +17,10 @@ TESTS = \
 	next-001.sh \
 	search-001.sh
 
+TESTS_ENVIRONMENT = \
+	CALCURSE='$(top_builddir)/src/calcurse' \
+	DATA_DIR='$(top_srcdir)/test/data/'
+
 AM_CFLAGS = -std=c99 -pedantic -D_POSIX_C_SOURCE=200809L
 
 check_PROGRAMS = run-test