procps-ng: Fix installation and take precedence over busybox

Currently procps-ng binaries are installed under $(TARGET_DIR)/usr/usr
instead of $(TARGET_DIR)/usr, which would be the expected. This is
caused because the default value of the --exec-prefix configure option
is /usr, and Buildroot always adds --prefix=/usr to the configure
option. We fix this by setting --exec-prefix to an empty value.

At the same time we make sure the procps-ng binaries have precedence
over the busybox ones.

Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Reviewed-by: Markos.Chandras <Markos.Chandras@imgtec.com>
Acked-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/procps-ng/procps-ng.mk

@@ -13,9 +13,19 @@ PROCPS_NG_INSTALL_STAGING = YES
 
 PROCPS_NG_DEPENDENCIES = ncurses
 
+# If both procps-ng and busybox are selected, make certain procps-ng
+# wins the fight over who gets to have their utils actually installed.
+ifeq ($(BR2_PACKAGE_BUSYBOX),y)
+PROCPS_NG_DEPENDENCIES += busybox
+endif
+
 ifeq ($(BR2_NEEDS_GETTEXT_IF_LOCALE),y)
 PROCPS_NG_DEPENDENCIES += gettext
 PROCPS_NG_CONF_OPT += LIBS=-lintl
 endif
 
+# We need this to make procps-ng binaries installed in $(TARGET_DIR)/usr
+# instead of $(TARGET_DIR)/usr/usr
+PROCPS_NG_CONF_OPT += --exec-prefix=
+
 $(eval $(autotools-package))