Fix a Makefile issue, and add a test exposing an OSR bug

src/Makefile

@@ -164,7 +164,7 @@ LDFLAGS_RELEASE := $(LLVM_RELEASE_LDFLAGS) $(COMMON_LDFLAGS)
 # LDFLAGS_RELEASE += -Wl,--gc-sections
 
 BUILD_SYSTEM_DEPS := Makefile Makefile.local $(wildcard build_system/*)
-CLANG_DEPS := $(CLANG_EXE) $(dir $(CLANG_EXE))/../../built_release
+CLANG_DEPS := $(CLANG_EXE) $(abspath $(dir $(CLANG_EXE))/../../built_release)
 
 # settings to make clang and ccache play nicely:
 CLANG_CCACHE_FLAGS := -Qunused-arguments

test/tests/osr_maybe_undefined.py

+# Regression test to make sure we can do an OSR if one of the live variables
+# is potentially-undefined.
+
+def f(x):
+    if x:
+        y = 1
+
+    for i in xrange(10000000):
+        pass
+
+    print y
+f(1)
+f(0)