[makefile] use PREFIX and OPAM_SWITCH_PREFIX

doc/Makefile

@@ -28,7 +28,7 @@ MAKECONFIG_DIR=$(FRAMAC_SRC)/share
 
 include $(FRAMAC_SRC)/share/Makefile.common
 
-FRAMAC_DOCDIR ?= $(DOCDIR)/frama-c
+FRAMAC_DOCDIR ?= $(PREFIX)/share/doc/frama-c
 
 .PHONY: .force
 
@@ -217,6 +217,5 @@ endif
 
 help::
 	@echo "Documentation installation configuration variable"
-	@echo "  - PREFIX: documentation will be in PREFIX/share/doc/frama-c"
-	@echo "  - DOCDIR: (overrides previous variable) documentation will be in DOCDIR/frama-c"
-	@echo "  - FRAMAC_DOCDIR: (overrides previous variable) documentation will be in FRAMAC_DOCDIR"
+	@echo "  - PREFIX: by default, documentation will be generated in PREFIX/share/doc/frama-c"
+	@echo "  - FRAMAC_DOCDIR: if set, documentation will be in FRAMAC_DOCDIR"

share/Makefile.common

@@ -50,16 +50,16 @@ DUNE_BUILD_OPTS+=--display $(DUNE_DISPLAY)
 PLATFORM:=$(shell uname -s)
 
 #############
-# Locations #
+# Install   #
 #############
 
-# Note that Dune rules do NOT use these variables.
-# They are used by other Makefiles
-#   - Ivette (PREFIX)
-#   - Manuals (DOCDIR)
-
-PREFIX ?= /usr/local
-DOCDIR ?= $(PREFIX)/share/doc
+ifndef PREFIX
+ifdef OPAM_SWITCH_PREFIX
+PREFIX=$(OPAM_SWITCH_PREFIX)
+else
+PREFIX=/usr/local
+endif
+endif
 
 #############
 # Verbosing #

share/Makefile.installation

@@ -28,18 +28,13 @@
 ## Help
 
 help::
-	@echo "Installation configuration variables"
-	@echo "  - PREFIX: used to customize installation path"
-	@echo "  - MANDIR: used to customize man files installation path"
+	@echo "Installation configuration variables:"
+	@echo "  - PREFIX: target installation prefix (default is OPAM switch or /usr/local)"
+	@echo "  - MANDIR: custom installation for man pages"
 
 ################################
-## Default variables
+## Man Path
 
-# Set this variable to request a specific installation directory
-# Default: Dune installs in the Opam directory
-PREFIX?=
-
-# Set this variable to request a specific man installation directory
 # Default: the manuals are installed in the installation directory transmitted
 # to Dune (so either in Opam or in PREFIX)
 MANDIR?=
@@ -55,20 +50,24 @@ endif
 
 .PHONY: install uninstall
 
-install:
-ifeq ($(PREFIX),)
-	dune install ${MANDIR_OPT}
+install::
+ifndef PREFIX
+	@echo "Warning: cannot install Frama-C: no PREFIX defined, nor OPAM."
+	@exit 1
+else
+ifeq ($(PREFIX),$(OPAM_SWITCH_PREFIX))
+	@echo "Installing Frama-C to current Opam switch"
+	dune install ${MANDIR_OPT} 2> /dev/null
 else
-	@echo "Installing to prefix: ${PREFIX}"
-	dune install --prefix ${PREFIX} ${MANDIR_OPT}
+	@echo "Installing Frama-C to ${PREFIX}"
+	dune install --prefix ${PREFIX} ${MANDIR_OPT} 2> /dev/null
 	@echo 'DO NOT FORGET TO EXPAND YOUR OCAMLPATH VARIABLE:'
 	@echo '  export OCAMLPATH="${PREFIX}/lib:$$OCAMLPATH"'
 endif
+endif
 
-uninstall:
-ifeq ($(PREFIX),)
-	dune uninstall ${MANDIR_OPT}
-else
-	@echo "Uninstalling from prefix: ${PREFIX}"
-	dune uninstall --prefix ${PREFIX} ${MANDIR_OPT}
+ifdef PREFIX
+uninstall::
+	@echo "Uninstalling Frama-C"
+	dune uninstall --prefix ${PREFIX} ${MANDIR_OPT} 2> /dev/null
 endif