Makefile: Spelling fixes

Correct typos of the following word families:

libraries
install
overwrite

ASTERISK-29714

Change-Id: I6488814f79186d6c23dfd7b7f9bba0a046126174

Makefile

@@ -21,7 +21,7 @@
 #      on a single object just for that object
 # SOLINK - linker flags used only for creating dynamically loadable modules
 #          as .so files
-# DYLINK - linker flags used only for creating shared libaries
+# DYLINK - linker flags used only for creating shared libraries
 #          (.so files on Unix-type platforms, .dylib on Darwin)
 #
 # Values for ASTCFLAGS and ASTLDFLAGS can be specified in the
@@ -135,7 +135,7 @@ empty:=
 space:=$(empty) $(empty)
 ASTTOPDIR:=$(subst $(space),\$(space),$(CURDIR))
 
-# Overwite config files on "make samples" or other config installation targets
+# Overwrite config files on "make samples" or other config installation targets
 OVERWRITE=y
 
 # Include debug and macro symbols in the executables (-g) and profiling info (-pg)