Merge #290: configure: Clean ups

860e3bb configure: Fix reduced surjection proof size (Tim Ruffing)
0873358 configure: Reorder modules also for AC_ARG_ENABLE (Tim Ruffing)
9de973f configure: Document canonical order of modules (Tim Ruffing)

Pull request description:

ACKs for top commit:
  jonasnick:
    ACK 860e3bb

Tree-SHA512: cfbaf9cb8a686aeab43ef6727b38d94467b862746062c1c06876bd98614ada7a00bc617481b0e0059dc294250a94a53581f3ffd685aa05c47a665950b280da51

configure.ac

@@ -168,24 +168,26 @@ AC_ARG_ENABLE(examples,
     AS_HELP_STRING([--enable-examples],[compile the examples [default=no]]), [],
     [SECP_SET_DEFAULT([enable_examples], [no], [yes])])
 
-AC_ARG_ENABLE(module_bppp,
-    AS_HELP_STRING([--enable-module-bppp],[enable Bulletproofs++ module (experimental)]),
-    [],
-    [SECP_SET_DEFAULT([enable_module_bppp], [no], [yes])])
-
 AC_ARG_ENABLE(module_ecdh,
     AS_HELP_STRING([--enable-module-ecdh],[enable ECDH module [default=yes]]), [],
     [SECP_SET_DEFAULT([enable_module_ecdh], [yes], [yes])])
 
-AC_ARG_ENABLE(module_musig,
-    AS_HELP_STRING([--enable-module-musig],[enable MuSig module (experimental)]),
-    [],
-    [SECP_SET_DEFAULT([enable_module_musig], [no], [yes])])
-
 AC_ARG_ENABLE(module_recovery,
     AS_HELP_STRING([--enable-module-recovery],[enable ECDSA pubkey recovery module [default=no]]), [],
     [SECP_SET_DEFAULT([enable_module_recovery], [no], [yes])])
 
+AC_ARG_ENABLE(module_extrakeys,
+    AS_HELP_STRING([--enable-module-extrakeys],[enable extrakeys module [default=yes]]), [],
+    [SECP_SET_DEFAULT([enable_module_extrakeys], [yes], [yes])])
+
+AC_ARG_ENABLE(module_schnorrsig,
+    AS_HELP_STRING([--enable-module-schnorrsig],[enable schnorrsig module [default=yes]]), [],
+    [SECP_SET_DEFAULT([enable_module_schnorrsig], [yes], [yes])])
+
+AC_ARG_ENABLE(module_ellswift,
+    AS_HELP_STRING([--enable-module-ellswift],[enable ElligatorSwift module [default=yes]]), [],
+    [SECP_SET_DEFAULT([enable_module_ellswift], [yes], [yes])])
+
 AC_ARG_ENABLE(module_generator,
     AS_HELP_STRING([--enable-module-generator],[enable NUMS generator module [default=no]]),
     [],
@@ -196,28 +198,35 @@ AC_ARG_ENABLE(module_rangeproof,
     [],
     [SECP_SET_DEFAULT([enable_module_rangeproof], [no], [yes])])
 
+AC_ARG_ENABLE(module_surjectionproof,
+    AS_HELP_STRING([--enable-module-surjectionproof],[enable surjection proof module [default=no]]),
+    [],
+    [SECP_SET_DEFAULT([enable_module_surjectionproof], [no], [yes])])
+AC_ARG_ENABLE(reduced_surjection_proof_size,
+    AS_HELP_STRING([--enable-reduced-surjection-proof-size],[use reduced surjection proof size (disabling parsing and verification) [default=no]]),
+    [],
+    [SECP_SET_DEFAULT([enable_reduced_surjection_proof_size], [no], [no])])
+
 AC_ARG_ENABLE(module_whitelist,
     AS_HELP_STRING([--enable-module-whitelist],[enable key whitelisting module [default=no]]),
     [],
     [SECP_SET_DEFAULT([enable_module_whitelist], [no], [yes])])
 
-AC_ARG_ENABLE(module_extrakeys,
-    AS_HELP_STRING([--enable-module-extrakeys],[enable extrakeys module [default=yes]]), [],
-    [SECP_SET_DEFAULT([enable_module_extrakeys], [yes], [yes])])
-
-AC_ARG_ENABLE(module_schnorrsig,
-    AS_HELP_STRING([--enable-module-schnorrsig],[enable schnorrsig module [default=yes]]), [],
-    [SECP_SET_DEFAULT([enable_module_schnorrsig], [yes], [yes])])
-
-AC_ARG_ENABLE(module_ellswift,
-    AS_HELP_STRING([--enable-module-ellswift],[enable ElligatorSwift module [default=yes]]), [],
-    [SECP_SET_DEFAULT([enable_module_ellswift], [yes], [yes])])
+AC_ARG_ENABLE(module_musig,
+    AS_HELP_STRING([--enable-module-musig],[enable MuSig module (experimental)]),
+    [],
+    [SECP_SET_DEFAULT([enable_module_musig], [no], [yes])])
 
 AC_ARG_ENABLE(module_ecdsa_s2c,
     AS_HELP_STRING([--enable-module-ecdsa-s2c],[enable ECDSA sign-to-contract module [default=no]]),
     [],
     [SECP_SET_DEFAULT([enable_module_ecdsa_s2c], [no], [yes])])
 
+AC_ARG_ENABLE(module_bppp,
+    AS_HELP_STRING([--enable-module-bppp],[enable Bulletproofs++ module (experimental)]),
+    [],
+    [SECP_SET_DEFAULT([enable_module_bppp], [no], [yes])])
+
 AC_ARG_ENABLE(module_ecdsa-adaptor,
     AS_HELP_STRING([--enable-module-ecdsa-adaptor],[enable ECDSA adaptor module [default=no]]),
     [],
@@ -227,16 +236,6 @@ AC_ARG_ENABLE(external_default_callbacks,
     AS_HELP_STRING([--enable-external-default-callbacks],[enable external default callback functions [default=no]]), [],
     [SECP_SET_DEFAULT([enable_external_default_callbacks], [no], [no])])
 
-AC_ARG_ENABLE(module_surjectionproof,
-    AS_HELP_STRING([--enable-module-surjectionproof],[enable surjection proof module [default=no]]),
-    [],
-    [SECP_SET_DEFAULT([enable_module_surjectionproof], [no], [yes])])
-
-AC_ARG_ENABLE(reduced_surjection_proof_size,
-    AS_HELP_STRING([--enable-reduced-surjection-proof-size],[use reduced surjection proof size (disabling parsing and verification) [default=no]]),
-    [],
-    [SECP_SET_DEFAULT([use_reduced_surjection_proof_size], [no], [no])])
-
 # Test-only override of the (autodetected by the C code) "widemul" setting.
 # Legal values are:
 #  * int64 (for [u]int64_t),
@@ -527,7 +526,7 @@ if test x"$enable_external_default_callbacks" = x"yes"; then
   SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DUSE_EXTERNAL_DEFAULT_CALLBACKS=1"
 fi
 
-if test x"$use_reduced_surjection_proof_size" = x"yes"; then
+if test x"$enable_reduced_surjection_proof_size" = x"yes"; then
   SECP_CONFIG_DEFINES="$SECP_CONFIG_DEFINES -DUSE_REDUCED_SURJECTION_PROOF_SIZE=1"
 fi
 
@@ -610,6 +609,10 @@ AC_SUBST(LIB_VERSION_AGE, _LIB_VERSION_AGE)
 
 AC_OUTPUT
 
+# The order in which all modules are listed here should be considered the
+# canonical order. This order (or, when appropriate, its reserve) should be used
+# everywhere we list or process modules, i.e., here and in other build system
+# files and docs.
 echo
 echo "Build Options:"
 echo "  with external callbacks = $enable_external_default_callbacks"
@@ -623,9 +626,13 @@ echo "  module recovery         = $enable_module_recovery"
 echo "  module extrakeys        = $enable_module_extrakeys"
 echo "  module schnorrsig       = $enable_module_schnorrsig"
 echo "  module ellswift         = $enable_module_ellswift"
+# libsecp256k1-zkp modules, in the order they were added to the libsecp256k1-zkp
 echo "  module generator        = $enable_module_generator"
 echo "  module rangeproof       = $enable_module_rangeproof"
 echo "  module surjectionproof  = $enable_module_surjectionproof"
+if test x"$enable_module_surjectionproof" = x"yes" && test x"$enable_reduced_surjection_proof_size" = x"yes"; then
+echo "    reduced proof size    = $enable_reduced_surjection_proof_size"
+fi
 echo "  module whitelist        = $enable_module_whitelist"
 echo "  module musig            = $enable_module_musig"
 echo "  module ecdsa-s2c        = $enable_module_ecdsa_s2c"