Use make flags to help control where the library is installed

Where the library is installed has quite an affect on what -L and -I
flags are used.  If you install into the toolchain, you don't want
to use them at all, but if you install out of tree (/opt/mycm3 for
example) you need to specify the -L and -I flags.

Update the documentation and the example makefiles to support this

Makefile

@@ -19,7 +19,13 @@
 
 PREFIX		?= arm-none-eabi
 #PREFIX		?= arm-elf
+
+ifeq ($(DETECT_TOOLCHAIN),)
 DESTDIR		?= /usr/local
+else
+DESTDIR		?= $(shell dirname $(shell readlink -f $(shell which $(PREFIX)-gcc)))/..
+endif
+
 INCDIR		= $(DESTDIR)/$(PREFIX)/include
 LIBDIR		= $(DESTDIR)/$(PREFIX)/lib
 SHAREDIR	= $(DESTDIR)/$(PREFIX)/share/libopencm3/scripts

README

@@ -48,7 +48,8 @@ Example projects
 
 The library ships with a few small example projects which illustrate how
 individual subsystems of the microcontrollers can be configured and used with
-libopencm3.
+libopencm3. The makefiles are generally useable for your own projects with
+only minimal changes for the libopencm3 install path (See Installation)
 
 For flashing the 'miniblink' example (after you built libopencm3 and the
 examples by typing 'make' at the top-level directory) onto the Olimex
@@ -79,16 +80,23 @@ Installation
 
  $ make install
 
-This will install the library in /usr/local. If you want to install it
-elsewhere, use the following syntax:
+This will install the library into /usr/local. (permissions permitting)
 
- $ DESTDIR=/opt make install
+If you want to install it elsewhere, use the following syntax:
 
-The recommended location is to install into your toolchain directory, e.g.
-/home/someuser/sat for a toolchain built using the summon-arm-toolchain
-script from https://github.com/esden/summon-arm-toolchain.
+ $ make DESTDIR=/opt/libopencm3 install
 
- $ DESTDIR=~/sat make install
+If you want to attempt to install into your toolchain, use this:
+
+ $ make DETECT_TOOLCHAIN=1 install
+
+Note: If you install this into your toolchain, you don't need to pass
+any extra -L or -I flags into your projects.  However, this also means
+you must NOT pass any -L or -I flags that point into the toolchain. This
+_will_ confuse the linker.  (ie, for summon-arm-toolchain, do NOT pass
+-L/home/user/sat/lib) Common symptoms of confusing
+the linker are hard faults caused by branches into arm code.
+You can use objdump to check for this in your final elf.
 
 
 Coding style and development guidelines

examples/stm32/f1/Makefile.include

@@ -45,6 +45,15 @@ LDFLAGS		+= --static -Wl,--start-group -lc -lgcc -lnosys -Wl,--end-group \
 		   -L$(TOOLCHAIN_DIR)/lib \
 		   -T$(LDSCRIPT) -nostartfiles -Wl,--gc-sections \
 		   $(ARCH_FLAGS) -mfix-cortex-m3-ldrd
+
+ifneq ($(OPENCM3_DIR),)
+CFLAGS          += -I$(OPENCM3_DIR)/include
+LDFLAGS         += -L$(OPENCM3_DIR)/lib -L$(OPENCM3_DIR)/lib/stm32/f1
+SCRIPT_DIR      = $(OPENCM3_DIR)/share
+else
+SCRIPT_DIR      = $(shell dirname $(shell readlink -f $(shell which $(PREFIX)-gcc)))/../$(PREFIX)/share
+endif
+
 OBJS		+= $(BINARY).o
 
 OOCD		?= openocd
@@ -53,6 +62,9 @@ OOCD_BOARD	?= olimex_stm32_h103
 # Black magic probe specific variables
 # Set the BMP_PORT to a serial port and then BMP is used for flashing
 BMP_PORT        ?=
+# texane/stlink can be used by uncommenting this...
+# or defining it in your own makefiles
+#STLINK_PORT ?= :4242
 
 # Be silent per default, but 'make V=1' will show all compiler calls.
 ifneq ($(V),1)
@@ -107,6 +119,7 @@ clean:
 	$(Q)rm -f *.srec
 	$(Q)rm -f *.list
 
+ifeq ($(STLINK_PORT),)
 ifeq ($(BMP_PORT),)
 ifeq ($(OOCD_SERIAL),)
 %.flash: %.hex
@@ -140,6 +153,14 @@ else
 		   -x $(TOOLCHAIN_DIR)/scripts/black_magic_probe_flash.scr \
 		   $(*).elf
 endif
+else
+%.flash: %.elf
+	@echo "  GDB   $(*).elf (flash)"
+	$(Q)$(GDB) --batch \
+		   -ex 'target extended-remote $(STLINK_PORT)' \
+		   -x $(SCRIPT_DIR)/libopencm3/scripts/stlink_flash.scr \
+		   $(*).elf
+endif
 
 .PHONY: images clean