check vigorously for installed mkimage

It was briefly mentioned in QUICKSTART but somehow managed
to evade the commandlines provided.  And while at it, let's
make errors like this more explicit to avoid extra lookups.
Oh, and fix QUICKSTART so that readers miss the hassle. :)

Thanks Vladimir Karpinsky for pointing this problem out.

QUICKSTART

@@ -15,7 +15,7 @@
 команды
 ~~~~~~~
 - от имени root:
-# apt-get install hasher git-core
+# apt-get install mkimage hasher git-core
 # hasher-useradd USER
 
 - от имени пользователя (после повторного входа):

image.in/Makefile

@@ -10,8 +10,10 @@ MKI_VER_OPTIMAL = 0.2.0
 
 include distcfg.mk
 include functions.mk
-include $(MKIMAGE_PREFIX)/config.mk
 
+ifeq (,$(realpath $(MKIMAGE_PREFIX)/config.mk))
+$(error please apt-get install mkimage and have a look at QUICKSTART as well)
+endif
 ifeq (-,$(shell rpmvercmp $(MKI_VERSION) $(MKI_VER_MINIMAL) | tr -d [0-9]))
 $(info error: mkimage-$(MKI_VERSION) is too old, please upgrade)
 $(error mkimage is too old, $(MKI_VER_MINIMAL) is minimal supported version)
@@ -21,6 +23,8 @@ $(info warning: mkimage-$(MKI_VERSION) is suboptimal, consider upgrading)
 $(warning consider upgrading mkimage to $(MKI_VER_OPTIMAL) or better)
 endif
 
+include $(MKIMAGE_PREFIX)/config.mk
+
 # reconstruct instead of passing yet another variable
 IMAGE_LINK := $(IMAGE_NAME).$(IMAGE_TYPE)
 IMAGE_OUTFILE := $(IMAGE_NAME)-$(DATE)-$(ARCH).$(IMAGE_TYPE)

lib/build.mk

@@ -45,8 +45,8 @@ build-image: profile/populate
 	if $(START) $(MAKE) -C $(BUILDDIR)/ $(LOG); then \
 		echo "$(TIME) done (`tail -1 $(BUILDLOG) | cut -f1 -d.`)"; \
 		tail -200 "$(BUILDLOG)" $(SHORTEN) \
-		| GREP_COLOR="$(ANSI_OK)" \
-		  grep --color=auto '^\*\* image: .*' ||:; \
+		| GREP_COLOR="$(ANSI_OK)" GREP_OPTIONS="--color=auto" \
+		  grep '^\*\* image: .*' ||:; \
 	else \
 		echo -n "$(TIME) failed, see log"; \
 		if [ -z "$(DEBUG)" ]; then \
@@ -56,8 +56,8 @@ build-image: profile/populate
 			echo " above"; \
 		fi; \
 		tail -200 "$(BUILDLOG)" \
-		| GREP_COLOR="$(ANSI_FAIL)" \
-		  egrep --color=auto "^(E:|[Ee]rror|[Ww]arning).*"; \
+		| GREP_COLOR="$(ANSI_FAIL)" GREP_OPTIONS="--color=auto" \
+		  egrep "^((E:|[Ee]rror|[Ww]arning).*)|(.* Stop\.)$$"; \
 		df -P $(BUILDDIR) | awk 'END { if ($$4 < $(LOWSPACE)) \
 			{ print "NB: low space on "$$6" ("$$5" used)"}}'; \
 	fi; \