installsrc: build a non-AOT binary from source

Enabling Native AOT made install-from-source.sh fail across every
distro: linking a native binary needs a C toolchain (clang and zlib
headers) that the script does not install, so the publish aborts with
"gcc or clang is missing".

Installing from source does not need a native binary. Build a normal
framework-dependent one instead by setting PublishAot=false in the
environment for the build; the executable project now honours an
externally supplied PublishAot and the nested publish inherits it
through the packaging scripts. The shipped packages, which set nothing,
still default to AOT.

This keeps the only requirement for a source install the .NET SDK the
script already bootstraps, rather than a per-distro C toolchain.

Assisted-by: Claude Opus 4.8
Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>

Author: mjcheetham

src/linux/Packaging.Linux/install-from-source.sh

@@ -259,5 +259,9 @@ if [ -z "$DOTNET_ROOT" ]; then
 fi
 
 cd "$toplevel_path"
-$sudo_cmd env "PATH=$PATH" $DOTNET_ROOT/dotnet build ./src/linux/Packaging.Linux/Packaging.Linux.csproj -c Release -p:InstallFromSource=true -p:installPrefix=$installPrefix
+# Build a non-AOT binary so installing from source needs only the .NET SDK,
+# not a C toolchain (clang + zlib) to link a native build. PublishAot is read
+# from the environment by Git-Credential-Manager.csproj and inherited by the
+# nested publish.
+$sudo_cmd env "PATH=$PATH" PublishAot=false $DOTNET_ROOT/dotnet build ./src/linux/Packaging.Linux/Packaging.Linux.csproj -c Release -p:InstallFromSource=true -p:installPrefix=$installPrefix
 add_to_PATH "$installPrefix/bin"

src/shared/Git-Credential-Manager/Git-Credential-Manager.csproj

@@ -10,7 +10,10 @@
     <IsTestProject>false</IsTestProject>
     <LangVersion>latest</LangVersion>
     <TargetLatestRuntimePatch>true</TargetLatestRuntimePatch>
-    <PublishAot>true</PublishAot>
+    <!-- Produce a native AOT build by default. Building from source can set
+         PublishAot=false in the environment to opt out, so installing locally
+         doesn't require a C toolchain (clang + zlib) just to link. -->
+    <PublishAot Condition="'$(PublishAot)' == ''">true</PublishAot>
   </PropertyGroup>
 
   <ItemGroup>