diff --git a/Makefile b/Makefile
index e7e2e6eea..b92b9bbec 100644
--- a/Makefile
+++ b/Makefile
@@ -1,17 +1,15 @@
 EXECUTABLE = src/lamac
 INSTALL ?= install -v
 MKDIR ?= mkdir
-SHELL := /bin/bash
 
 .PHONY: all regression
 
 all:
-	make -C src 
-	make -C runtime 
-	make -C stdlib
+	$(MAKE) -C src
+	$(MAKE) -C runtime
+	$(MAKE) -C stdlib
 
 STD_FILES=$(shell ls stdlib/*.[oi] stdlib/*.lama runtime/runtime.a runtime/Std.i)
-#$(info $(STD_FILES))
 
 install: all
 	$(INSTALL) $(EXECUTABLE) `opam var bin`
@@ -23,13 +21,12 @@ uninstall:
 	$(RM) `opam var bin`/$(EXECUTABLE)
 
 regression:
-	make clean check -C regression
-	make clean check -C stdlib/regression
+	$(MAKE) clean check -C regression
+	$(MAKE) clean check -C stdlib/regression
 
 clean:
-	make clean -C src
-	make clean -C runtime
-	make clean -C stdlib
-	make clean -C regression
+	$(MAKE) clean -C src
+	$(MAKE) clean -C runtime
+	$(MAKE) clean -C stdlib
+	$(MAKE) clean -C regression
 	$(MAKE) clean -C bench
-
diff --git a/README.md b/README.md
index 9e2efce4a..419075f59 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ the domain of programming languages, compilers and tools. Its general characteri
 * with automatic memory management (garbage collection).
 
 The name ![lama](lama.png) is an acronym for *Lambda-Algol* since the language has borrowed the syntactic shape of
-operators from **Algol-68**; [**Haskell**](www.haskell.org) and [**OCaml**](www.ocaml.org) can be
+operators from **Algol-68**; [**Haskell**](http://www.haskell.org) and [**OCaml**](http://ocaml.org) can be
 mentioned as other languages of inspiration.
 
 The main purpose of ![lama](lama.png) is to present a repertoire of constructs with certain runtime behavior and
@@ -52,6 +52,12 @@ Windows users should get Windows Subsystem for Linux a.k.a WSL (recommended) or
 * System-wide prerequisites:
 
   - `sudo apt install gcc-multilib` (in Debian-based GNU/Linux)
+   
+     On some versions you need to install additional package `lib32gcc-9-dev` in case of errors like 
+       ```       
+      /usr/bin/ld: cannot find -lgcc
+      /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/9/libgcc.a when searching for -lgcc              
+       ```
   - [opam](http://opam.ocaml.org) (>= 2.0.4)
   - [OCaml](http://ocaml.org) (>= 4.10.1). *Optional* because it can be easily installed through opam. Compiler variant with `flambda` switch is recommended
 
@@ -98,6 +104,6 @@ Windows users should get Windows Subsystem for Linux a.k.a WSL (recommended) or
   /home/user/.opam/lama/bin/lamac
   ```
 
-### Smoke-testing:
+### Smoke-testing (optional)
 
-Clone the repository and run `make -C tutorial LAMAC=../src/lamac`. Without extra `LAMAC` switch it will try to use `lamac` installed system-wide to build tutorial.
+Clone the repository and run `make -C tutorial`. It should build local compiler `src/lamac` and a few tutorial executables in `tutorial/`.
diff --git a/runtime/Makefile b/runtime/Makefile
index 457906978..27657559f 100644
--- a/runtime/Makefile
+++ b/runtime/Makefile
@@ -1,12 +1,12 @@
+
 all: gc_runtime.o runtime.o
-	ar rc runtime.a gc_runtime.o runtime.o 
+	ar rc runtime.a gc_runtime.o runtime.o
 
 gc_runtime.o: gc_runtime.s
-	gcc -g -fstack-protector-all -m32 -c gc_runtime.s
+	$(CC) -g -fstack-protector-all -m32 -c gc_runtime.s
 
 runtime.o: runtime.c
-	gcc -g -fstack-protector-all -m32 -c runtime.c
+	$(CC) -g -fstack-protector-all -m32 -c runtime.c
 
 clean:
-	rm -f *.a *.o *~
-
+	$(RM) *.a *.o *~
diff --git a/src/Makefile b/src/Makefile
index af5d51222..710fb359f 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -24,7 +24,7 @@ $(TOPFILE).byte: $(SOURCES:.ml=.cmo)
 	$(OCAMLC) -o $(TOPFILE).byte $(BFLAGS) -linkpkg $(SOURCES:.ml=.cmo)
 
 clean:
-	rm -Rf *.cmi *.cmo *.cmx *.annot *.o *.opt *.byte *~ .depend
+	$(RM) $(TOPFILE) *.cm[ioxa] *.annot *.o *.opt *.byte *~ .depend
 
 -include .depend
 # generic rules
diff --git a/tutorial/Makefile b/tutorial/Makefile
index 014b24f20..9f879e826 100644
--- a/tutorial/Makefile
+++ b/tutorial/Makefile
@@ -1,13 +1,19 @@
-SHELL := /bin/bash
-
 FILES=$(wildcard *.lama)
 ALL=$(sort $(FILES:.lama=))
-LAMAC=lamac
+EXTRA_TARGETS =
 
-all: $(ALL)
+ifeq ($(LAMAC),)
+	LAMAC := ../src/lamac
+	EXTRA_TARGETS += $(LAMAC)
+endif
+
+all: $(EXTRA_TARGETS) $(ALL)
+
+../src/lamac:
+	$(MAKE) -C ../src
 
 %: %.lama
 	$(LAMAC) $<
 
 clean:
-	rm -Rf *.s *.o *.i *~ $(ALL)
+	$(RM) -R *.s *.o *.i *~ $(ALL)