build: explain current role of LIBS in our Makefile.am files

BLANK_AT_MAKETIME may be used in our Makefile.am files to blank
LIBS variable used in generated makefile at makefile processing
time. Doing this functionally prevents LIBS from being used for
all link targets in given makefile.

diff --git a/configure.ac b/configure.ac
index 0386d11..b8268b3 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -3364,12 +3364,11 @@ LIBCURL_LIBS=$LIBS
 AC_SUBST(LIBCURL_LIBS)
 AC_SUBST(CURL_NETWORK_LIBS)
 AC_SUBST(CURL_NETWORK_AND_TIME_LIBS)
-dnl LIBS is a magic variable that's used for every link
 
-dnl BLANK_AT_MAKETIME might be used in some of our Makefile.am files to
-dnl blank LIBS variable used in generated makefile at makefile processing
-dnl time. Our test server's Makefile.am uses this to prevent global LIBS
-dnl from being used for any test server build target.
+dnl BLANK_AT_MAKETIME may be used in our Makefile.am files to blank
+dnl LIBS variable used in generated makefile at makefile processing
+dnl time. Doing this functionally prevents LIBS from being used for
+dnl all link targets in given makefile.
 BLANK_AT_MAKETIME=
 AC_SUBST(BLANK_AT_MAKETIME)
 

diff --git a/docs/examples/Makefile.am b/docs/examples/Makefile.am
index 49c2036..865f093 100644 (file)
--- a/docs/examples/Makefile.am
+++ b/docs/examples/Makefile.am
@@ -48,7 +48,7 @@ if USE_CPPFLAG_CURL_STATICLIB
 AM_CPPFLAGS += -DCURL_STATICLIB
 endif
 
-# Prevent global LIBS from influencing examples build targets
+# Prevent LIBS from being used for all link targets
 LIBS = $(BLANK_AT_MAKETIME)
 
 # Dependencies

diff --git a/lib/Makefile.am b/lib/Makefile.am
index c8a88cd..9179026 100644 (file)
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -132,7 +132,7 @@ if VERSIONED_SYMBOLS
 VERSIONED_SYMBOLS = -Wl,--version-script=libcurl.vers
 endif
 
-# Prevent global LIBS from influencing lib build targets
+# Prevent LIBS from being used for all link targets
 LIBS = $(BLANK_AT_MAKETIME)
 
 libcurl_la_LDFLAGS = $(UNDEF) $(VERSIONINFO) $(MIMPURE) $(VERSIONED_SYMBOLS) $(LIBCURL_LIBS)

diff --git a/src/Makefile.am b/src/Makefile.am
index 7839904..6de7501 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -54,7 +54,7 @@ include Makefile.inc
 # This might hold -Werror
 CFLAGS += @CURL_CFLAG_EXTRAS@ @LIBMETALINK_CFLAGS@
 
-# Prevent global LIBS from influencing src build targets
+# Prevent LIBS from being used for all link targets
 LIBS = $(BLANK_AT_MAKETIME)
 
 if USE_EXPLICIT_LIB_DEPS

diff --git a/tests/libtest/Makefile.am b/tests/libtest/Makefile.am
index a9d0b90..df13df1 100644 (file)
--- a/tests/libtest/Makefile.am
+++ b/tests/libtest/Makefile.am
@@ -55,8 +55,7 @@ test1022.pl Makefile.inc notexists.pl
 
 CFLAG_CURL_SYMBOL_HIDING = @CFLAG_CURL_SYMBOL_HIDING@
 
-# Prevent global LIBS from influencing libtest build targets
-BLANK_AT_MAKETIME = @BLANK_AT_MAKETIME@
+# Prevent LIBS from being used for all link targets
 LIBS = $(BLANK_AT_MAKETIME)
 
 if USE_EXPLICIT_LIB_DEPS

diff --git a/tests/server/Makefile.am b/tests/server/Makefile.am
index 85e0c09..d4ef252 100644 (file)
--- a/tests/server/Makefile.am
+++ b/tests/server/Makefile.am
@@ -50,8 +50,7 @@ AM_CPPFLAGS = -I$(top_builddir)/include/curl \
               -I$(top_srcdir)/lib
 endif
 
-# Prevent global LIBS from influencing test server build targets
-BLANK_AT_MAKETIME = @BLANK_AT_MAKETIME@
+# Prevent LIBS from being used for all link targets
 LIBS = $(BLANK_AT_MAKETIME)
 
 if DOING_NATIVE_WINDOWS

diff --git a/tests/unit/Makefile.am b/tests/unit/Makefile.am
index 0582168..eb29241 100644 (file)
--- a/tests/unit/Makefile.am
+++ b/tests/unit/Makefile.am
@@ -54,7 +54,10 @@ endif
 
 EXTRA_DIST = Makefile.inc
 
-LDADD = $(top_builddir)/lib/libcurlu.la @LDFLAGS@ @LIBCURL_LIBS@ @LIBS@
+# Prevent LIBS from being used for all link targets
+LIBS = $(BLANK_AT_MAKETIME)
+
+LDADD = $(top_builddir)/lib/libcurlu.la @LDFLAGS@ @LIBCURL_LIBS@
 DEPENDENCIES = $(top_builddir)/lib/libcurlu.la
 AM_CPPFLAGS += -DUNITTESTS