[build] Stop readline macro from polluting the environment variables.

m4/lnav_with_readline.m4

@@ -42,6 +42,9 @@ AC_DEFUN([AX_PATH_LIB_READLINE],
         [with_readline="yes"]
     )dnl
 
+    AS_VAR_SET(saved_CFLAGS, $CFLAGS)
+    AS_VAR_SET(saved_CPPFLAGS, $CPPFLAGS)
+    AS_VAR_SET(saved_LDFLAGS, $LDFLAGS)
     AS_CASE(["$with_readline"],
         [no],
         AC_MSG_ERROR([readline required to build]),
@@ -49,6 +52,8 @@ AC_DEFUN([AX_PATH_LIB_READLINE],
         [],
         [dnl
         AS_VAR_SET([READLINE_CFLAGS], ["-I$with_readline/include"])
+        AS_VAR_SET([READLINE_LDFLAGS], ["-L$with_readline/lib"])
+        LNAV_ADDTO(CFLAGS, [-I$with_readline/include])
         LNAV_ADDTO(CPPFLAGS, [-I$with_readline/include])
         dnl We want the provided path to be the first in the search order.
         LDFLAGS="-L$with_readline/lib $LDFLAGS"
@@ -61,6 +66,14 @@ AC_DEFUN([AX_PATH_LIB_READLINE],
         [$CURSES_LIB]dnl
     )dnl
 
+    dnl Ensure that the readline library has the required symbols.
+    dnl i.e. We haven't picked up editline.
+    AC_SEARCH_LIBS([history_set_history_state], [readline],
+        [],
+        AC_MSG_ERROR([libreadline does not have the required symbols. editline possibly masquerading as readline.]),
+        [$CURSES_LIB]dnl
+    )
+
     AC_CHECK_HEADERS([readline.h readline/readline.h],
         [dnl
         AS_VAR_SET([HAVE_READLINE_HEADERS], [1])
@@ -68,20 +81,15 @@ AC_DEFUN([AX_PATH_LIB_READLINE],
         ]dnl
     )
 
-
     AS_VAR_SET_IF([HAVE_READLINE_HEADERS], [],
         [AC_MSG_ERROR([readline headers not found])]
     )
-
-    dnl Ensure that the readline library has the required symbols.
-    dnl i.e. We haven't picked up editline.
-    AC_SEARCH_LIBS([history_set_history_state], [readline],
-        [],
-        AC_MSG_ERROR([libreadline does not have the required symbols. editline possibly masquerading as readline.]),
-        [$CURSES_LIB]dnl
-    )
+    AS_VAR_SET(CFLAGS, $saved_CFLAGS)
+    AS_VAR_SET(CPPFLAGS, $saved_CPPFLAGS)
+    AS_VAR_SET(LDFLAGS, $saved_LDFLAGS)
 
     AC_SUBST([READLINE_LIBS])
     AC_SUBST([READLINE_CFLAGS])
+    AC_SUBST([READLINE_LDFLAGS])
     ]dnl
 )dnl

src/Makefile.am

@@ -54,6 +54,7 @@ time_fmts.cc: ptimec
 
 AM_LDFLAGS = \
 	$(STATIC_LDFLAGS) \
+	$(READLINE_LDFLAGS) \
 	$(SQLITE3_LDFLAGS) \
 	$(PCRE_LDFLAGS) \
 	-pthread
@@ -61,6 +62,7 @@ AM_LDFLAGS = \
 AM_CPPFLAGS = \
 	-DSYSCONFDIR='"$(sysconfdir)"' \
 	-Wall \
+	$(READLINE_CFLAGS) \
 	$(SQLITE3_CFLAGS)
 
 LDADD = \

test/Makefile.am

@@ -16,6 +16,7 @@ simple-db.db: simple-db.sql
 
 AM_CPPFLAGS = \
 	-I$(top_srcdir)/src \
+	$(READLINE_CFLAGS) \
 	$(SQLITE3_CFLAGS)
 
 # AM_CFLAGS = -fprofile-arcs -ftest-coverage
@@ -56,6 +57,7 @@ check_PROGRAMS = \
 AM_LDFLAGS = \
 	$(STATIC_LDFLAGS) \
 	$(SQLITE3_LDFLAGS) \
+	$(READLINE_LDFLAGS) \
 	-pthread
 
 LDADD = -lz