use function pointers instead of weak symbols for cmdline parsing

Passing function pointers around while working on this was very icky,
but if weak symbols are too much to ask for…

Reverts "do not use "-Wl,-Bsymbolic-functions" during the build to avoid
breakage" aka a5fc9be36211a290a7abc3ca2a8bf98943bc1f57.

apt-private/private-cmndline.cc

@@ -378,7 +378,8 @@ static void ShowHelpListCommands(std::vector<aptDispatchWithHelp> const &Cmds)/*
    }
 }
 									/*}}}*/
-static bool ShowCommonHelp(APT_CMD const Binary, CommandLine &CmdL, std::vector<aptDispatchWithHelp> const &Cmds)/*{{{*/
+static bool ShowCommonHelp(APT_CMD const Binary, CommandLine &CmdL, std::vector<aptDispatchWithHelp> const &Cmds,/*{{{*/
+      bool (*ShowHelp)(CommandLine &))
 {
    std::cout << PACKAGE << " " << PACKAGE_VERSION << " (" << COMMON_ARCH << ")" << std::endl;
    if (_config->FindB("version") == true && Binary != APT_CMD::APT_GET)
@@ -442,7 +443,8 @@ static void BinarySpecificConfiguration(char const * const Binary)	/*{{{*/
 }
 									/*}}}*/
 std::vector<CommandLine::Dispatch> ParseCommandLine(CommandLine &CmdL, APT_CMD const Binary,/*{{{*/
-      Configuration * const * const Cnf, pkgSystem ** const Sys, int const argc, const char *argv[])
+      Configuration * const * const Cnf, pkgSystem ** const Sys, int const argc, const char *argv[],
+      bool (*ShowHelp)(CommandLine &), std::vector<aptDispatchWithHelp> (*GetCommands)(void))
 {
    if (Cnf != NULL && pkgInitConfig(**Cnf) == false)
    {
@@ -477,7 +479,7 @@ std::vector<CommandLine::Dispatch> ParseCommandLine(CommandLine &CmdL, APT_CMD c
        (Sys != NULL && pkgInitSystem(*_config, *Sys) == false))
    {
       if (_config->FindB("version") == true)
-	 ShowCommonHelp(Binary, CmdL, CmdsWithHelp);
+	 ShowCommonHelp(Binary, CmdL, CmdsWithHelp, ShowHelp);
 
       _error->DumpErrors();
       exit(100);
@@ -487,12 +489,12 @@ std::vector<CommandLine::Dispatch> ParseCommandLine(CommandLine &CmdL, APT_CMD c
    if (_config->FindB("help") == true || _config->FindB("version") == true ||
 	 (CmdL.FileSize() > 0 && strcmp(CmdL.FileList[0], "help") == 0))
    {
-      ShowCommonHelp(Binary, CmdL, CmdsWithHelp);
+      ShowCommonHelp(Binary, CmdL, CmdsWithHelp, ShowHelp);
       exit(0);
    }
    if (Cmds.empty() == false && CmdL.FileSize() == 0)
    {
-      ShowCommonHelp(Binary, CmdL, CmdsWithHelp);
+      ShowCommonHelp(Binary, CmdL, CmdsWithHelp, ShowHelp);
       exit(1);
    }
    return Cmds;
@@ -514,7 +516,3 @@ unsigned short DispatchCommandLine(CommandLine &CmdL, std::vector<CommandLine::D
    return Errors == true ? 100 : 0;
 }
 									/*}}}*/
-
-// weak symbols
-bool ShowHelp(CommandLine &) { return false; }
-std::vector<aptDispatchWithHelp> GetCommands() { return {}; }

apt-private/private-cmndline.h

@@ -33,7 +33,8 @@ struct aptDispatchWithHelp
 APT_PUBLIC std::vector<aptDispatchWithHelp> GetCommands() APT_WEAK;
 
 APT_PUBLIC std::vector<CommandLine::Dispatch> ParseCommandLine(CommandLine &CmdL, APT_CMD const Binary,
-      Configuration * const * const Cnf, pkgSystem ** const Sys, int const argc, const char * argv[]);
+      Configuration * const * const Cnf, pkgSystem ** const Sys, int const argc, const char * argv[],
+      bool (*ShowHelp)(CommandLine &), std::vector<aptDispatchWithHelp> (*GetCommands)(void));
 APT_PUBLIC unsigned short DispatchCommandLine(CommandLine &CmdL, std::vector<CommandLine::Dispatch> const &Cmds);
 
 APT_PUBLIC std::vector<CommandLine::Args> getCommandArgs(APT_CMD const Program, char const * const Cmd);

cmdline/apt-cache.cc

@@ -1247,7 +1247,7 @@ int main(int argc,const char *argv[])					/*{{{*/
 
    // Parse the command line and initialize the package library
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_CACHE, &_config, &_system, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_CACHE, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    InitOutput();
 

cmdline/apt-cdrom.cc

@@ -229,7 +229,7 @@ int main(int argc,const char *argv[])					/*{{{*/
 
    // Parse the command line and initialize the package library
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_CDROM, &_config, &_system, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_CDROM, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    InitOutput();
 

cmdline/apt-config.cc

@@ -101,7 +101,7 @@ int main(int argc,const char *argv[])					/*{{{*/
 
    // Parse the command line and initialize the package library
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_CONFIG, &_config, &_system, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_CONFIG, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    std::vector<std::string> const langs = APT::Configuration::getLanguages(true);
    _config->Clear("Acquire::Languages");

cmdline/apt-extracttemplates.cc

@@ -342,7 +342,7 @@ int main(int argc, const char **argv)					/*{{{*/
 	InitLocale();
 
 	CommandLine CmdL;
-	auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_EXTRACTTEMPLATES, &_config, &_system, argc, argv);
+	auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_EXTRACTTEMPLATES, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
 	Go(CmdL);
 

cmdline/apt-get.cc

@@ -434,7 +434,7 @@ int main(int argc,const char *argv[])					/*{{{*/
 
    // Parse the command line and initialize the package library
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_GET, &_config, &_system, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_GET, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    InitSignals();
    InitOutput();

cmdline/apt-helper.cc

@@ -131,7 +131,7 @@ int main(int argc,const char *argv[])					/*{{{*/
    InitLocale();
 
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_HELPER, &_config, &_system, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_HELPER, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    InitOutput();
 

cmdline/apt-internal-solver.cc

@@ -71,7 +71,7 @@ int main(int argc,const char *argv[])					/*{{{*/
 	DropPrivileges();
 
 	CommandLine CmdL;
-	ParseCommandLine(CmdL, APT_CMD::APT_INTERNAL_SOLVER, &_config, NULL, argc, argv);
+	ParseCommandLine(CmdL, APT_CMD::APT_INTERNAL_SOLVER, &_config, NULL, argc, argv, &ShowHelp, &GetCommands);
 
 	if (CmdL.FileList[0] != 0 && strcmp(CmdL.FileList[0], "scenario") == 0)
 	{

cmdline/apt-mark.cc

@@ -322,7 +322,7 @@ int main(int argc,const char *argv[])					/*{{{*/
    InitLocale();
 
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_MARK, &_config, &_system, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_MARK, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    InitOutput();
 

cmdline/apt-sortpkgs.cc

@@ -155,7 +155,7 @@ int main(int argc,const char *argv[])					/*{{{*/
    InitLocale();
 
    CommandLine CmdL;
-   ParseCommandLine(CmdL, APT_CMD::APT_SORTPKG, &_config, &_system, argc, argv);
+   ParseCommandLine(CmdL, APT_CMD::APT_SORTPKG, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    // Match the operation
    for (unsigned int I = 0; I != CmdL.FileSize(); I++)

cmdline/apt.cc

@@ -100,7 +100,7 @@ int main(int argc, const char *argv[])					/*{{{*/
    InitLocale();
 
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT, &_config, &_system, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT, &_config, &_system, argc, argv, &ShowHelp, &GetCommands);
 
    int const quiet = _config->FindI("quiet", 0);
    if (quiet == 2)

debian/rules

@@ -29,10 +29,7 @@ ifneq (,$(shell which dpkg-buildflags))
   # (http://savannah.gnu.org/bugs/?10593)
   dpkg_buildflags = DEB_BUILD_MAINT_OPTIONS=hardening=+all dpkg-buildflags
   export CXXFLAGS = $(shell $(dpkg_buildflags) --get CXXFLAGS)
-  # we can not use "-Wl,-Bsymbolic-functions" with the new weak symbols
-  # in libapt-private (commit 28f24d3d added those)
-  comma:= ,
-  export LDFLAGS = $(subst -Wl$(comma)-Bsymbolic-functions,,$(shell $(dpkg_buildflags) --get LDFLAGS))
+  export LDFLAGS = $(shell $(dpkg_buildflags) --get LDFLAGS)
   export CPPFLAGS = $(shell $(dpkg_buildflags) --get CPPFLAGS)
 else
   ifneq (,$(findstring noopt,$(DEB_BUILD_OPTIONS)))

ftparchive/apt-ftparchive.cc

@@ -1048,7 +1048,7 @@ int main(int argc, const char *argv[])					/*{{{*/
 
    // Parse the command line and initialize the package library
    CommandLine CmdL;
-   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_FTPARCHIVE, &_config, NULL, argc, argv);
+   auto const Cmds = ParseCommandLine(CmdL, APT_CMD::APT_FTPARCHIVE, &_config, NULL, argc, argv, ShowHelp, &GetCommands);
 
    _config->CndSet("quiet",0);
    Quiet = _config->FindI("quiet",0);