diff --git a/src/Makefile.am b/src/Makefile.am
index 7a0ca2985..f405331d6 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -410,6 +410,10 @@ TESTS_ENVIRONMENT = \
 	MAKE="$(MAKE) $(AM_MAKEFLAGS)" \
 	HBSOURCES="$(HBSOURCES)" \
 	HBHEADERS="$(HBHEADERS)" \
+	LDD="$(LDD)" \
+	NM="$(NM)" \
+	OBJDUMP="$(OBJDUMP)" \
+	OTOOL="$(OTOOL)" \
 	$(NULL)
 
 if HAVE_INTROSPECTION
diff --git a/src/check-libstdc++.py b/src/check-libstdc++.py
index 200c68374..85b726531 100755
--- a/src/check-libstdc++.py
+++ b/src/check-libstdc++.py
@@ -6,13 +6,11 @@ os.chdir (os.getenv ('srcdir', os.path.dirname (__file__)))
 
 libs = os.getenv ('libs', '.libs')
 
-ldd = shutil.which ('ldd')
-if ldd:
-	ldd = [ldd]
-else:
-	ldd = shutil.which ('otool')
-	if ldd:
-		ldd = [ldd, '-L'] # otool -L
+ldd = os.getenv ('LDD', shutil.which ('ldd'))
+if not ldd:
+	otool = os.getenv ('OTOOL', shutil.which ('otool'))
+	if otool:
+		ldd = otool + ' -L'
 	else:
 		print ('check-libstdc++.py: \'ldd\' not found; skipping test')
 		sys.exit (77)
@@ -27,7 +25,7 @@ for soname in ['harfbuzz', 'harfbuzz-subset', 'harfbuzz-gobject']:
 		if not os.path.exists (so): continue
 
 		print ('Checking that we are not linking to libstdc++ or libc++ in %s' % so)
-		ldd_result = subprocess.check_output (ldd + [so])
+		ldd_result = subprocess.check_output (ldd.split() + [so])
 		if (b'libstdc++' in ldd_result) or (b'libc++' in ldd_result):
 			print ('Ouch, %s is linked to libstdc++ or libc++' % so)
 			stat = 1
diff --git a/src/check-static-inits.py b/src/check-static-inits.py
index 1c88f22ca..813295d57 100755
--- a/src/check-static-inits.py
+++ b/src/check-static-inits.py
@@ -5,7 +5,7 @@ import sys, os, shutil, subprocess, glob, re
 builddir = os.getenv ('builddir', os.path.dirname (__file__))
 libs = os.getenv ('libs', '.libs')
 
-objdump = shutil.which ('objdump')
+objdump = os.getenv ('OBJDUMP', shutil.which ('objdump'))
 if not objdump:
 	print ('check-static-inits.py: \'ldd\' not found; skipping test')
 	sys.exit (77)
@@ -22,7 +22,7 @@ if not OBJS:
 stat = 0
 
 for obj in OBJS:
-	result = subprocess.check_output ([objdump, '-t', obj]).decode ('utf-8')
+	result = subprocess.check_output (objdump.split () + ['-t', obj]).decode ('utf-8')
 
 	# Checking that no object file has static initializers
 	for l in re.findall (r'^.*\.[cd]tors.*$', result, re.MULTILINE):
diff --git a/src/check-symbols.py b/src/check-symbols.py
index c366dc0aa..8050e1bf9 100755
--- a/src/check-symbols.py
+++ b/src/check-symbols.py
@@ -11,7 +11,7 @@ IGNORED_SYMBOLS = '|'.join(['_fini', '_init', '_fdata', '_ftext', '_fbss',
 	'__bss_start', '__bss_start__', '__bss_end__', '_edata', '_end', '_bss_end__',
 	'__end__', '__gcov_.*', 'llvm_.*', 'flush_fn_list', 'writeout_fn_list', 'mangle_path'])
 
-nm = shutil.which ('nm')
+nm = os.getenv ('NM', shutil.which ('nm'))
 if not nm:
 	print ('check-symbols.py: \'nm\' not found; skipping test')
 	sys.exit (77)
@@ -30,8 +30,8 @@ for soname in ['harfbuzz', 'harfbuzz-subset', 'harfbuzz-icu', 'harfbuzz-gobject'
 		symprefix = '_' if suffix == 'dylib' else ''
 
 		EXPORTED_SYMBOLS = [s.split ()[2]
-							for s in re.findall (r'^.+ [BCDGIRST] .+$', subprocess.check_output ([nm, so]).decode ('utf-8'), re.MULTILINE)
-							if not re.match (r'.* %s(%s)\b' % (symprefix, IGNORED_SYMBOLS), s)]
+				    for s in re.findall (r'^.+ [BCDGIRST] .+$', subprocess.check_output (nm.split() + [so]).decode ('utf-8'), re.MULTILINE)
+				    if not re.match (r'.* %s(%s)\b' % (symprefix, IGNORED_SYMBOLS), s)]
 
 		# run again c++flit also if is available
 		if cxxflit:
diff --git a/src/gen-ragel-artifacts.py b/src/gen-ragel-artifacts.py
index b60ec3bff..d22e03ae3 100755
--- a/src/gen-ragel-artifacts.py
+++ b/src/gen-ragel-artifacts.py
@@ -4,7 +4,7 @@
 
 import os, os.path, sys, subprocess, shutil
 
-ragel = shutil.which ('ragel')
+ragel = os.getenv ('RAGEL', shutil.which ('ragel'))
 if not ragel:
 	sys.exit ('You have to install ragel if you are going to develop HarfBuzz itself')
 
@@ -19,7 +19,7 @@ outdir = os.path.dirname (OUTPUT)
 shutil.copy (INPUT, outdir)
 rl = os.path.basename (INPUT)
 hh = rl.replace ('.rl', '.hh')
-subprocess.Popen ([ragel, '-e', '-F1', '-o', hh, rl], cwd=outdir).wait ()
+subprocess.Popen (ragel.split() + ['-e', '-F1', '-o', hh, rl], cwd=outdir).wait ()
 
 # copy it also to src/
 shutil.copyfile (os.path.join (outdir, hh), os.path.join (CURRENT_SOURCE_DIR, hh))