Fix cross-machine build: HDF5 target conflict and Eigen3 detection

Author: dav-og

CMakeLists.txt

@@ -168,6 +168,12 @@ if(NOT Chrono_DIR)
     return()
 endif()
 
+# Pre-load HDF5 targets so the shims below are only created when genuinely
+# needed (i.e., when HDF5 config-mode doesn't provide hdf5_tools).
+# Without this, installers that define all HDF5 targets as a batch
+# (e.g., HDF Group installer) error out on the partial pre-definition.
+find_package(HDF5 CONFIG QUIET)
+
 # Chrono's export file may reference hdf5::hdf5_tools-{shared,static} which is
 # absent from some HDF5 installations (e.g., vcpkg). Provide empty shims so
 # ChronoTargets.cmake loads without errors. Must be created BEFORE find_package(Chrono).
@@ -250,9 +256,8 @@ endif()
 find_package(OpenMP REQUIRED COMPONENTS CXX)
 
 # -- HDF5 Integration --
-# Prefer config-mode (vcpkg, official HDF5 installer).  Fall back to CMake's
-# built-in FindHDF5 module for system-installed packages (apt, yum, brew, etc.).
-find_package(HDF5 CONFIG QUIET)
+# Config-mode discovery runs early (before Chrono) to avoid target conflicts
+# with the hdf5_tools shims. Fall back to module-mode here if it wasn't found.
 if(NOT HDF5_FOUND)
     find_package(HDF5 REQUIRED COMPONENTS CXX)
 endif()

build.ps1

@@ -154,7 +154,7 @@ if (-not $hasHDF5) {
 # Eigen3: extract include path from Chrono config so FindEigen3.cmake can
 # bypass Eigen3ConfigVersion.cmake (Eigen 5.x rejects the "3.3" request).
 $eigen3Include = $null
-if ($chronoContent -match 'Eigen3_DIR\s+"([^"]+)"') {
+if ($chronoContent -match 'Eigen3_DIR\s+"([^"]+)"' -and $Matches[1] -notmatch 'NOTFOUND') {
     $eigen3Root = Split-Path (Split-Path $Matches[1])
     $candidate = Join-Path $eigen3Root "include/eigen3"
     if (Test-Path (Join-Path $candidate "Eigen")) {
@@ -164,6 +164,15 @@ if ($chronoContent -match 'Eigen3_DIR\s+"([^"]+)"') {
         Write-Warn "Eigen3 headers not found at $candidate"
     }
 }
+if (-not $eigen3Include -and $chronoContent -match 'EIGEN3_INCLUDE_DIR\s+"([^"]+)"' -and $Matches[1] -notmatch 'NOTFOUND') {
+    $candidate = $Matches[1]
+    if (Test-Path (Join-Path $candidate "Eigen")) {
+        $eigen3Include = $candidate
+        Write-OK "Eigen3: $eigen3Include (via EIGEN3_INCLUDE_DIR)"
+    } else {
+        Write-Warn "Eigen3 headers not found at $candidate"
+    }
+}
 
 # =============================================================================
 # Check CMake