The -no-undefined flag is CRUCIAL for this to build fine on Cygwin. If we

find a case in which we need to remove this flag, we should most likely
write a configure check that detects when this flag is needed and when its
not.

lib/Makefile.am

@@ -16,7 +16,12 @@ lib_LTLIBRARIES = libcurl.la
 # we use srcdir/lib for the lib-private header files
 INCLUDES = -I$(top_srcdir)/include -I$(top_builddir)/lib -I$(top_srcdir)/lib
 
-libcurl_la_LDFLAGS = -version-info 2:2:0
+# The -no-undefined flag is CRUCIAL for this to build fine on Cygwin. If we
+# find a case in which we need to remove this flag, we should most likely
+# write a configure check that detects when this flag is needed and when its
+# not.
+libcurl_la_LDFLAGS = -no-undefined -version-info 2:2:0
+
 # This flag accepts an argument of the form current[:revision[:age]]. So,
 # passing -version-info 3:12:1 sets current to 3, revision to 12, and age to
 # 1.