new file mode 100644
--- /dev/null
+++ b/.lldbinit
@@ -0,0 +1,7 @@
+# .lldbinit file for debugging Mozilla
+
+# Mozilla's use of UNIFIED_SOURCES to include multiple source files into a
+# single compiled file breaks lldb breakpoint setting. This works around that.
+# See http://lldb.llvm.org/troubleshooting.html for more info.
+settings set target.inline-breakpoint-strategy always
+

--- a/build/Makefile.in
+++ b/build/Makefile.in
@@ -71,16 +71,25 @@ endif
 
 # Put a useful .gdbinit in the bin directory, to be picked up automatically
 # by GDB when we debug executables there.
 # NOTE: Keep .gdbinit in the topsrcdir for people who run gdb from the topsrcdir.
 GDBINIT_FILES := $(topsrcdir)/.gdbinit
 GDBINIT_DEST = $(FINAL_TARGET)
 INSTALL_TARGETS += GDBINIT
 
+# Put a useful .lldbinit in the bin directory, to be picked up automatically
+# by LLDB when we debug executables using that directory as the current working
+# directory.
+# NOTE: Keep .lldbinit in the topsrcdir for people who run LLDB from the
+# topsrcdir rather than the bin directory.
+LLDBINIT_FILES := $(topsrcdir)/.lldbinit
+LLDBINIT_DEST = $(FINAL_TARGET)
+INSTALL_TARGETS += LLDBINIT
+
 include $(topsrcdir)/config/rules.mk
 
 # we install to _leaktest/
 TARGET_DEPTH = ..
 include $(srcdir)/automation-build.mk
 
 _LEAKTEST_DIR = $(DEPTH)/_leaktest